Patent Description:
Chain actuators are popular because the push pull chain is stiff when extended but at the same time the chain can fold one way and wind up to be stored less visible for example along a window side. Chain actuators are compact and generally enable good application into windows.

Usually the push pull chain obtains stiff stability by bending beyond a straight line. A further benefit is that this also allows the chain to follow the opening radius of the window wing like shown in <CIT>. Such chain following the radius of the wing is not part of the present invention.

Prior art has suggested chain end connectors with springs and chain ends with offset connection. One example is shown in <CIT> where <FIG> shows a push pull chain having the extended position angle alfa of <NUM> degrees or more. <CIT> shows another example of a chain actuator wherein the chain ends with an offset connection.

<CIT> also shows a push pull chain (fig 11a) which loads the chain by an inclined chain end connector fig 10b (<NUM>).

<CIT> also shows a chain bending back beyond a straight line to obtain stability.

In the present disclosure by chain is understood a push pull chain which has a stiff configuration and a folded configuration.

It is an object to provide a window having an improved chain actuator with increased load and/or stroke.

Also it is an object to better utilize the chain capacity to allow smaller dimensions of the actuator. Because the chain actuator size affects the size of the window profiles in applications where the actuator is hidden in the window.

Also it is an object to better utilize the chain capacity for applications in roof windows, where the chain must carry some of the window weight and the chain actuator must be oversized to accommodate heavy snow loads.

The foregoing and other objects are achieved by the features of the independent claim. Further implementation forms are apparent from the dependent claims.

According to the invention, there is provided a window comprising a frame, a movable sash, and an actuator from which a chain extends, the chain having an end connector and being configured to open and close the sash, the actuator being pivotably hinged at an axis to one of the frame and the sash, and the end connector being pivotably hinged at an axis to the other of the frame and the sash, the chain has a chain back where chain links engage to form a stiff chain, the stiff chain does not bend back past a straight line for stiffness, rather in an unloaded state the stiff chain bends forward, the chain has an end connector with a finger portion extending away from and past the chain back,.

Hereby the window actuator chain is favorably stabilized which enables smaller dimensions and/or larger stroke. Furthermore, the end of the chain is easily connected to the sash of the window during install/assembly. Additionally, it is possible to separate the position of the load force and the pull force. As a bonus the elongated openings also allow the end connector to tilt and keep the chain sides parallel.

In a possible implementation of the invention, the finger portion extends beyond a chain exit.

Hereby the load force is transferred such that the chain is stable.

In a further possible implementation of the invention, the imaginary vector line does not intersect the chain center line.

Hereby the chain does not risk sudden decrease of the load capacity.

In a further possible implementation of the invention, the chain end connector applies an increasing moment which increases with increased load force.

Hereby the chain capacity is increased compared to other stabilizing solutions such as a spring, which merely generates a constant moment.

In a further possible implementation of the invention, the chain end connector does not apply an increasing moment when pulling with a pull force.

Hereby the chain may pull without the stabilizing effect is reversed into a destabilizing effect.

In a further possible implementation of the invention, the pull force is substantially applied at the chain center line.

Hereby a neutral pull force is provided which does not destabilize the chain when pulling or under fluctuating loads.

In a further possible implementation of the invention, the pull force is more towards the front of the chain than the load force which is more to the back of the chain. Hereby the chain is stabilized under load without the pulling forces destabilize the chain. For example, a wind draft can change the direction from load to pull instantly.

In a further possible implementation of the invention, the extended chain sides are substantially straight and parallel.

Hereby both sides of the chain are loaded equally and the chain capacity is enhanced to allow larger load and/or stoke. For a tilting window this may require the chain actuator and the chain end connector is hinged.

In a further possible implementation of the invention, the finger portion and/or the start of the imaginary vector line extend behind the chain back by at least twice the amount which the chain bends forward in the unloaded stiff state.

Hereby the chain obtains stability and enhanced load capacity. Also the chain remains stable if impacted, which may otherwise cause the chain to collapse.

In a further possible implementation of the invention, the unloaded chain bends forward relative to a straight line at least <NUM>, such as at least <NUM>.

Hereby it is ensured the chain does not bend backwards past a straight line.

In a further possible implementation of the invention, where in a loaded state the stiff chain bends forward.

Hereby the chain does not bend past a straight line when stiff but bends the opposite way. And with increased load the chain deforms towards a straight line and gains increased capacity.

In a further possible implementation of the invention, the actuator is hidden inside the sash or inside the frame or in a cavity between the sash and frame.

Hereby the actuator is architecturally pleasing and well protected from the climate and burglars. In such configurations it is usually favorable the dimensions of the actuator are small.

In a further possible implementation of the invention, the window is a roof window and the chain supports at least part of the sash weight.

Hereby the high load capacity allows a roof window which can withstand a possible snow load. A further benefit is that the chain is stable under changing load conditions due to different roof angles and possible window addons such as roller shutters.

This and other possible implementations of the invention will be apparent from the embodiments described below.

In the following detailed portion of the present disclosure, the invention will be explained in more detail with reference to the example embodiments shown in the drawings, in which:.

<FIG> shows a window comprising a moving sash <NUM> and a frame <NUM> adapted for receiving the sash <NUM>. The sash <NUM> is hinged to rotate about an axis or the hinges can provide a combined rotation and displacement or a parallel displacement etc..

At least one push pull chain actuator is configured to open and close the sash. The chain actuator has an extending chain <NUM> and the actuator housing is connected to the frame and the chain end is connected to the sash. A vice versa arrangement is also possible. In examples the chain actuator housing is hidden in the window frame or hidden in the window sash or hidden in a cavity between the sash and frame. The chain actuator provides a pull force PF when retracting the chain <NUM> and pulling a window member. The chain actuator provides a load force LF when extending the chain <NUM> and pushing on a window member.

<FIG> shows the interior of a push pull chain actuator also known as a thrust chain because it can transmit a push force i.e. load force LF.

The chain actuator has a housing and the chain extends and retracts through an opening in the housing. The chain extends substantially perpendicular to the elongated housing. The chain actuator bends the chain when the chain is stored for example in two or more layers. The chain <NUM> extends substantially perpendicular to the stored layer(s) direction. This provides a compact solution which is advantageous. The chain actuator housing may be hinged to the window so the housing can tilt <NUM> during the opening movement.

The chain is driven by an electric motor <NUM>. A reduction gear <NUM> comprising a worm and/or multiple gears drive the final sprocket gear <NUM> which engages the chain. A chain guide <NUM> (not shown in <FIG>) guides the chain towards the exit where the chain becomes stable. However different gear configurations may be used and the chain actuator does not need a sprocket to push the chain, but can also use a spindle etc..

The chain <NUM> has a back <NUM> where links engage to carry a push load. In this example the chain back <NUM> has a closed back where the links use the width of the chain for engagement. Other chain designs are also possible. The extending end <NUM> of the chain <NUM> is connected to a window member.

<FIG> shows the chain front and <FIG> shows the chain back and <FIG> shows a similar chain from the side and according to scale in an unloaded state.

The chain <NUM> comprises links <NUM> joined by pins <NUM> which allow rotation in a chain plane P. And the pin <NUM> rotation axis is perpendicular to the chain plane.

The chain <NUM> has a chain front <NUM> with links <NUM> which allows bending forwards.

The chain <NUM> has a back <NUM> with links <NUM> which engage to form a stiff chain with limited bending backwards.

The chain has sides 7a,7b which extend between the chain front <NUM> and the chain back <NUM>.

A chain center line extends through an imaginary line iC crossing through the pins <NUM> of the stiff chain and hereafter called center line iC.

<FIG> shows an example of a chain with an open back i.e. a see through back. Here both the inner and outer links <NUM> engage on each chain side 7a,7b. So the total push load is distributed among four chain links.

This example also shows the chain <NUM> is straight in the plane P. In other words the chain sides 7a,7b are substantially straight and parallel. Hereby the load is divided evenly on both sides of the chain and this allows a better capacity rating. And possibly a larger opening stroke and/or smaller dimensions of the actuator and window.

<FIG> shows a different chain with a little different link design. However the overall function is the same as previous figures. The chain here is unloaded and according to scale.

And it is visible that the chain <NUM> is not completely straight. Nor does the chain bend back past a straight line.

<FIG> shows the chain <NUM> bends forward. In one example the chain is <NUM> long and at the middle D it bends substantially <NUM>. In general terms the chain forward bending is curved with a height of <NUM>-<NUM>, such as <NUM>-<NUM> at the middle (vertex) for a <NUM> chain. In more general terms the chain bends forward at the middle D by <NUM>% to <NUM>% of the chain stroke in the unloaded state. By forward bending chain is understood, that the chain engaging links <NUM> form an angle of less than <NUM> degrees around the chain pins <NUM>.

A roof window for example can load the chain with <NUM> and this naturally makes the chain deform a little under load. By employing a forward bent chain <NUM> together with an end connector <NUM> (explained later) a stabilizing effect can be obtained which allows larger capacity and/or stroke.

<FIG> shows an exaggerated bending figure to explain the forces. The push pull chain <NUM> has engaged the back links <NUM> and is stiff and extended. The chain <NUM> bends forward and has an end connector <NUM> at the extended chain end. The end connector <NUM> applies a load force (LF) at an imaginary vector line iL located behind the stiff chain <NUM>. Naturally the load can be applied at a surface or at multiple locations or at a single location. But the resulting load force LF vector is at the imaginary vector line iL. The end connector may for example be L or T shaped as explained later. To ensure the stabilizing effect the imaginary vector line iL does not intersect the forward bent chain <NUM> center line iC. The chain center line iC substantially meets the imaginary vector line iL at the chain actuator exit <NUM> where the chain links exit and achieve the stable and stiff chain configuration. The chain exit <NUM> is where the chain guide <NUM> terminates and where the chain <NUM> achieves stiffness and exits the housing.

The chain <NUM> deforms under heavy load. And a regular chain which bends beyond a straight line to obtain stiffness will gradually loose capacity with increased deformation. The current chain however bends forward in an unloaded stiff state. And the current chain will become more straight under load and gain load capacity.

The end connector <NUM> transfers the load force LF and pull force PF differently, meaning the load force LF automatically increases a moment M which maintains the chain stable with increased load. On the other hand the pull force PF acts at a different position where a more neutral pull can be provided.

Generally, if the pull was located at the same position as the load, then the forward <NUM> bent chain <NUM> would be urged towards possible collapse and failure. So the chain <NUM> end connector <NUM> transfers the pull force PF elsewhere than the imaginary vector line iL. In one embodiment the pull force PF acts substantially at the chain <NUM> center line iC. In one embodiment the pull force PF acts closer to the chain center line iC than to the imaginary vector line iL. Generally, all these effects are fulfilled by the end connector <NUM> described next.

<FIG> shows the push pull chain <NUM> with an end connector <NUM> provided at the extending chain end. And the figure illustrates the chain rotates about <NUM>° to the front <NUM> in the stored configuration. The end connector <NUM> is connected to the last chain link. The end connector <NUM> extends along the direction from the back side <NUM> of the chain to the front side <NUM> of the chain. An engagement surface 11b located at the top of the end connector <NUM> and it transfers the load force LF only from a window member or from a bracket <NUM> on a window member. The end connector <NUM> with a finger portion 11a applies a one way load force LF at an imaginary vector line iL located behind the stiff chain center line iC. The pull force PF is transferred elsewhere from the load force LF. The end connector <NUM> extends into a finger portion 11a in the direction of the back side <NUM> of the chain. The finger portion 11a extends in the chain plane P. The finger portion 11a extends such that the load force LF is provided behind the chain back <NUM>. The finger portion 11a is offset from the chain exit <NUM> in the chain backwards <NUM> direction. The finger portion 11a extends opposite of the forward bent chain <NUM>. The load force LF which is applied at the finger portion 11a is transferred through an imaginary vector line iL located behind the stiff chain back <NUM>. The finger portion 11a and the start of the imaginary vector line iL extend behind the chain back <NUM> by at least twice the amount, which the chain <NUM> bends forward in the unloaded stiff configuration. Understood so that if the stiff unloaded chain bends forward by <NUM>, then the finger portion 11a and the start of the imaginary vector line iL extends at least <NUM> behind the chain back <NUM>.

The imaginary vector line iL extends from the finger potion 11a to the chain exit <NUM>. At the chain exit <NUM> the imaginary vector line iL substantially meets the chain back. The imaginary vector line iL may move from the finger portion 11a along the engagement surface 11b when the chain deforms under heavy load, so <FIG> does not illustrate a permanent situation. The engagement surface 11b is inclined so the finger portion 11a is towards the top and/or so that the finger portion 11a is the point of load engagement. This ensures the load force LF is applied at the finger potion 11a. The finger portion 11a generally prevents the chain <NUM> from bending forwards. The end connector <NUM> has a threaded hole 11c and a fastener <NUM>. The threaded hole 11c is substantially located at the chain center line iC. The fastener <NUM> transfers the pull force PF. A bracket <NUM> is located at a window member. The bracket <NUM> has elongated openings <NUM>,<NUM> which connect with the fastener <NUM>. The elongated opening <NUM>,<NUM> are elongated in the chain stroke direction and the top of the openings <NUM>,<NUM> will never contact the fastener <NUM>. The surface 11b will contact the bracket <NUM> before the fastener <NUM>. Hereby it is ensured, that the fastener transfers a pull force (PF) only. Further the openings <NUM>,<NUM> also allow a pivoting movement so the chain sides 7a,7b can remain straight and parallel. Alternatively the openings <NUM>,<NUM> and the fastener <NUM> could be swapped, so the end connector <NUM> would have an elongated hole and the bracket <NUM> could have a thread for the fastener <NUM>. Also the fastener <NUM> could be a pin or a hook suitable to pull.

Generally the shape of the end connector <NUM> can be different. The end connector may be L or Y or T shaped or be formed from a rod or a special chain link etc. This particular end connector <NUM> and bracket <NUM> design example is simply chosen to favor quick assembly in the window.

<FIG> shows a further enhanced embodiment with a window configuration with the chain actuator <NUM>. The actuator <NUM> is hinged at an axis <NUM>. The chain end connector <NUM> is hinged at a parallel axis <NUM>. Hereby the chain <NUM> is neutral straight in the sideway 7a,7b direction and the chain remains in the straight chain plane P. And the opening sash radius r does not require the chain to bend sideways 7a,7b. Due to the hinged chain end connector <NUM> and the hinged actuator <NUM> the chain is straight and parallel in the sideway direction 7a,7b and an even further enhanced chain capacity and/or chain stroke is provided. The window has hinges which hold the sash <NUM> in the frame <NUM> and the actuator <NUM> hinged axis <NUM> and chain end connector axis <NUM> are located opposite to the window hinges. Generally the hinged actuator <NUM> axis <NUM> and chain end connector <NUM> axis are parallel with the window sash/frame side where the actuator is located. <FIG> shows a further enhanced embodiment with a window configuration where multiple chain actuators <NUM> open the window by parallel displacement (the frame <NUM> and sash <NUM> remain parallel). Due to the parallel displacement the chain is straight in the sideway direction 7a,7b and an even further enhanced chain capacity and/or chain stroke is provided. Windows with parallel displacement do not require the actuator or chain to be hinged. <FIG> show the actuator <NUM> at the frame <NUM>, but the actuator can also be switched to the sash <NUM> instead.

The inventors have realized maximizing the chain capacity allows for a more compact and slimmer design which has a synergistic effect on the overall window profile design and/or roof window design. Also enhancing the chain stability allows for larger opening stroke and larger window openings. Further the lifetime of the chain is increased due to wear on the chain links being counteracted by the chain stabilizing effect.

Further roof windows benefit due to varying roof angles and load conditions such as push pull situations which occur. Another benefit is a reduced need for window load balancing by counterweights or springs etc. so the springs / counterweights do not need adjustment or entirely may be omitted. The same applies when a retrofit shutter or snow adds weight to a window.

The invention has been described in conjunction with various embodiments herein. In the claims, the word "comprising" does not exclude other elements, and the indefinite article "a" or "an" does not exclude a plurality. The end connector <NUM> may be from multiple separate parts. For example the pull force (PL) and load force (LF) can be managed by separate parts. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage.

Claim 1:
A window comprising a frame (<NUM>), a movable sash (<NUM>), and an actuator (<NUM>) from which a chain (<NUM>) extends, the chain (<NUM>) having an end connector (<NUM>) and being configured to open and close the sash (<NUM>),
the actuator (<NUM>) being pivotably hinged at an axis (<NUM>) to one of the frame (<NUM>) and the sash (<NUM>), and the end connector (<NUM>) being pivotably hinged at an axis (<NUM>) to the other of the frame (<NUM>) and the sash (<NUM>),
wherein the chain (<NUM>) has a chain back (<NUM>) where chain links (<NUM>) engage to, and that when in a loaded state, form a stiff chain having a stiff chain center line (iC),
the chain (<NUM>) furthermore being configured such that, when in an unloaded state, the chain (<NUM>) does not bend back past the straight stiff chain center line (iC) and past the chain back (<NUM>), but rather bends forward past a chain front (<NUM>),
characterised in that the chain (<NUM>) has an end connector (<NUM>) with a finger portion (11a) extending away from and past the chain back (<NUM>),
an engagement surface (11b) of the finger portion (11a) being configured to apply a one way load force (LF) on a bracket (<NUM>) arranged on the sash (<NUM>) or the frame (<NUM>), at an imaginary vector line (iL) located past the stiff chain center line (iC) and past the chain back (<NUM>),
and the chain end connector (<NUM>) being configured to apply a pull force (PF) on the sash (<NUM>) or the frame (<NUM>) elsewhere than at the imaginary vector line (iL),
the end connector (<NUM>) being connected to the bracket (<NUM>) by means of a fastener (<NUM>) and one or more elongated openings (<NUM>,<NUM>) which allow a defined displacement in the chain stroke direction whereby only the pull force (PL) is transferred.