The present invention relates to a locking assem- bly for a ventilating window having a sash arranged to be openable with respect to a main frame by piv- otal movement about a pivot axis parallel to a pair of opposed sash members.

BACKGROUND OF THE INVENTION In a well known design, as disclosed e. g. in DK-C- 114,046, such a locking assembly comprises a strike plate with at least one stationary locking member se- cured to a main frame member opposite one of said pair of sash members and a casing secured to said one sash member opposite the strike plate. At least one pawl member is arranged in the casing to be movable between a locking position, in which it is in locking engagement with the stationary locking member and an unlocked position, in which it is released from said locking engagement to allow opening of the window.

A locking control mechanism arranged in the casing to control the movement of the pawl between the lock- ing and unlocked positions is connected with an op- erator member accessible from the inside of the win- dow via at least one actuator slide displaceable in guide means in the casing from a first end position defining the unlocked position of the pawl member to a second end position defining the locking position of the pawl member and vice versa via an intermediate position, and spring means is provided in the casing to act on the pawl member to force it to its locking position in the intermediate position of the slide.

The operator member is connected with the slide to occupy three distinct positions corresponding to the end positions and the intermediate position of the slide.

A locking assembly of this kind is conventionally used in roof windows, e. g. the well-known VELUXO win-

dows produced by the applicant. In such roof windows ventilation in the closed position of the sash with respect to the main frame may be provided for by means of an air flow passage formed between the sash member, to which the casing of the locking assembly is secured, and the opposite main frame member. A pivotal cover member connected with this sash member to open and close the air flow passage in the locked position of the sash with respect to the main frame forms the operator member for the actuator slide of the locking assembly.

DESCRIPTION OF THE PRIOR ART In view of the fact that in order to provide for air flow between the external and internal side of the window structure such a ventilation passage is open also to the external side of the window, al- though the external opening is hidden behind an ex- ternal top cover member, a certain risk exists for unauthorised operation of the actuator slide of the locking mechanism or the cover member for the air flow passage in the locked position of the sash with respect to the main frame, whereby access may be pro- vided to the interior of the building, in which the window is installed. Typically, attempts of such un- authorised operation may involve non-destructive in- troduction of a rigid instrument from the outside through the ventilation passage to push the actuator slide or the cover member towards the position, in which the locking of the sash with respect to the main frame is released.

To counteract this risk various blocking mecha- nisms for prevention of unauthorised operation of the cover member has been proposed in the prior art.

From DE-C-43 28 330 a blocking member is known comprising a key-operated cylinder lock secured in one of the main frame members perpendicular to the pivot axis in a position opposite one end of the

cover member. By key operation the cylinder of this locking member is moved by a spring load from a re- tracted position, in which it allows for opening of the sash, to a projecting position in which it blocks opening of the sash. Disadvantages of this solution are that the arrangement of the additional locking member on the inside of a main frame member will de- tract from the intended aesthetic appearance of the window and hat operation of the locking member re- quires a separate key, which may get lost.

From WO 99/10610 and WO 99/51832 it is known to arrange a blocking member preventing introduction of a rigid instrument from the outside in the ventila- tion passage itself either in the form of an insert box having at least two wall members providing a labyrinth-shaped ventilation passage or by securing a blocking plate member to the main frame member limit- ing the ventilation passage. Although these solutions avoid the disadvantages mentioned above by providing the blocking effect without any requirement of user operation they add significantly to complexity and costs in the production and/or installation of the window.

SUMMARY OF THE INVENTION It is the object of the invention to provide a locking assembly for a ventilating window of the kind defined, in which effective blocking against unau- thorised opening of the sash with respect to the main frame is provided by relatively simple and inexpen- sive blocking means.

According to the invention a locking assembly for a ventilating window is provided, having a sash ar- ranged to be openable with respect to a main frame by pivotal movement about a pivot axis parallel to a pair of opposed sash members, said locking assembly comprising a strike plate with at least one station- ary locking member secured to a main frame member op-

posite one of said pair of sash members and a casing secured to said one sash member opposite the strike plate, at least one pawl member arranged in said cas- ing to be movable between a locking position, in which it is in locking engagement with said station- ary locking member and an unlocked position, in which it is released from said locking engagement to allow opening of the window, a locking control mechanism arranged in said casing to control the movement of the pawl between said locking and unlocked positions, said locking control mechanism being operable by an operator member accessible from the inside of the window via at least one actuator slide displaceable in guide means in the casing from a first end posi- tion defining the unlocked position of the pawl mem- ber to a second end position defining the locking po- sition of the pawl member and vice versa via an in- termediate position, spring means in the casing act- ing on the pawl member to force it to its locking po- sition in said intermediate position of the slide, the operator member being connected with the slide to occupy three distinct positions corresponding to the end positions and the intermediate position of the slide, and is characterised in that blocking means is arranged in said casing to act on the locking con- trol mechanism and/or the actuator slide, said block- ing means being selectively operable by user operated means functionally integrated with said operator mem- ber for displacement between a blocking condition, in which the slide is prevented from displacement from the intermediate locking position to said first end position, and an non-blocking condition, in which the slide is freely displaceable in said guide means by operation of the operator member.

By the incorporation of the blocking means di- rectly in the casing of the locking assembly the need for installation of a blocking member in the ventila- tion passage, which inherently may affect the air

flow through the passage, is avoided and the blocking function can be implemented by relatively simple and inexpensive mechanical means.

In a preferred embodiment, the blocking function may be implemented, as stated in dependent claim 2, by a relatively simple modification of the conven- tional locking mechanism for a roof window disclosed in DK-C-114,046. In case of manual operation of the pivotal cover member of this embodiment the operating means for selective operation of said blocking member between its inoperative and operative positions may preferably be provided on a front side of said cover member and be connected with the blocking member by flexible connecting means, such as a bowden-cable.

In case of electrical operation of a window with such a locking assembly also the blocking means will preferably be electrically operated, e. g. by remote control.

BRIEF DESCRIPTION OF THE DRAWINGS In the following preferred and advantageous em- bodiments of the locking assembly according to the invention will be further elaborated with reference to the accompanying drawings, in which Fig. 1 is a sectional view of the upper part of a ventilating roof window incorporating a first embodi- ment of the locking assembly of the invention; Fig. 2 is a schematically plan view of the locking assembly sown in fig. 1 illustrating the functional co-operation between stationary locking members se- cured to the main frame and movable pawl members ar- ranged in a casing of the locking assembly; Fig. 3 is a schematically plan view of the compo- nents of the locking assembly arranged in the casing thereof in an unlocked position; Figs. 4 and 5 are schematically plan views in the direction of arrow IV, V in fig. 1 of the components of the locking assembly in a locking position with

blocking means as provided by the invention assuming a blocking position and a non-blocking position, re- spectively; Figs. 6 and 7 show the window part illustrated in fig. 1 from the inner and outer side of the window, respectively; Fig. 8 is a schematically plan view of an alterna- tive embodiment of the blocking mechanism; and Fig. 9 illustrates various phases of the operation of the blocking mechanism in fig. 8 DETAILLED DESCRIPTION In fig. 1 reference numerals 1 and 2 denote a top member of the main frame of a roof window and the top member of a pane supporting sash arranged in the main frame to be openable with respect thereto by pivotal movement about a pivot axis (not illustrated) paral- lel to top members 1 and 2.

Between opposing sides of main frame and sash top members 1 and 2 a clearance 3 is provided for ar- rangement of a locking assembly, by which the sash may be locked with respect to the main frame in the closed position of the sash. The clearance 3 forms in addition a ventilation passage allowing air flow be- tween the internal and external sides of the window in the closed position of the sash by operation of a cover member 4 that extends throughout the width of the sash and is connected with the sash top member 2 at the internal side of the window for pivotal move- ment between a closed position illustrated in solid lines and a ventilating position illustrated in dot- and-dash lines. As explained in more detail below the cover member is further linked with the locking as- sembly for the operation thereof.

In the illustrated embodiment the cover member 4 is provided with a handle 5 for manual operation.

The locking assembly comprises a strike plate 6 secured to the underside of the main frame top member

1. As shown in fig. 2 the strike plate 6 is provided at either end with a downwards directed projecting flap member 7, said flap members being arranged in symmetry with respect to a symmetry plane S illus- trated by a dashed line in fig. 2 forming a pair of stationary locking members. Between the two flap mem- bers 7 two further downwards directed flap 8 members form abutments for the locking mechanism to be de- scribed in more detail below.

The locking assembly further comprises a casing including a base plate 9 secured to the upper side of the sash top member 2 and a circumferential downwards directed edge wall 10. In the casing thus provided two movable pawl members 11 are pivotally suspended in symmetry with respect to the symmetry plane S to be movable between a locking position illustrated in fig. 2 and an unlocked position illustrated in fig.

3. Through a pair of circular tracks 12 formed in the base plate 9 in symmetry with respect to the symmetry plane S the pawl members 11 project out of the casing for engagement with the stationary locking members 7 and abutment members 8 of the strike plate 6.

The pawl members 11 are connected by separate locking control mechanisms with a common actuator slide 13 which is guided in guide means formed by a track 14 provided in the base plate 9 of the casing to extend in the symmetry plane S.

In each locking control mechanism first and second link arms 15 and 16 form a link joint. The first link arm 15 is bent at one end to form the upwards pro- jecting pawl member 11 and is suspended at the other end for pivotal movement about a stationary pin 17 in the casing. The second arm 16 is pivotally connected at one end with the first link arm 15 by means of a pin 18 and is pivotally connected at the other end with the actuator slide 13 by means of a pin 19.

As shown in figs 1 and 3 the common actuator slide 13 is further connected with one end of an operator

arm 20, the other end of which is pivotally connected with the cover member 4 by a suitable hinge member 21.

For each locking control mechanism a spring load is provided by means or a curved spring member 22 having a main portion positioned in a cut-out 23 in the second link arm 16 and projecting leg portions 24 and 24'engaging a pin member 25 secured to the base plate 9 and the pivot pin 18 connecting arms 15 and 16, respectively.

The function of the locking assembly so far de- scribed for locking and unlocking the sash with re- spect to the main frame is as follows.

In the unlocked position illustrated in fig. 3 the two pawl members 11 are located at the innermost ends of the circular tracks 12 and may pass freely in the direction of opening or closing the sash between the stationary locking members 7 secured to the main frame to allow opening of the sash with respect to the main frame. In this position the link joint is stretched with the first and second link arms 15 and 16 in substantially linear extension of each other, whereby the pawl members 11 will be prevented from displacement in their respective tracks 12 towards their locking positions in engagement with the sta- tionary locking members 7.

By movement of the sash in the closing direction the pawl members 11 thus released from any locking engagement will abut against the abutment flaps 8 of the strike plate 6 resulting in initial pivotal move- ment of each first link arm 15 about the stationary pin 17, Thereby, the first and second arms 15 and 16 of each link joints will be brought out of their po- sitions in linear extension of each other and, in re- sult, the pawl members 11 may be brought to their re- spective locking positions in engagement with locking members 7 as shown in fig. 4 by inwards movement of the actuator slide 13 caused by inwards movement of

the cover member 4 from its open position shown in dot-and-dash lines in fig. 1.

In the locking position shown in figs 4 and 5 the first and second arms 15 and 16 of each link joint extend substantially in L-shape with the second arms 16 of the two link joints in substantially linear ex- tension of each other. In this position of the lock- ing control mechanisms the actuator slide 13 may be moved further inwards in the guide track 14 to a sec- ond end position as illustrated in figs. 1 and 2.

Thereby, in the locking position the cover member 4 may be moved between the closed position shown in solid lines in fig. 1 and an intermediate ventilating position as shown in dot-and-dash lines, in which the ventilation passage 3 between the main frame and sash top members 1 and 2 is open for air flow between the external and internal sides of the window.

According to the invention a blocking mechanism is provided in the casing of the locking assembly to prevent movement of the pawl members 11 out of their respective locking engagement with the stationary locking members 7 of the strike plate 6 in the lock- ing position illustrated in fig. 4. In the embodiment shown the blocking mechanism comprises a blocking member 26 arranged in the casing for pivotal movement about a stationary pin member 27 between a blocking position as shown in fig. 4 and a released position as shown in fig. 5.

The blocking member 26 is formed with an upper edge 26a for engagement with the second link arm 16 of one of the link joints and with a generally curved or V-shaped lower edge comprising edge parts 26b and 26c defining the position of the blocking member 26 in the blocking and non-blocking positions, respec- tively by abutment against the wall 10 of the casing.

In the blocking position in fig. 4 defined by abutment of the edge part 26b against the casing wall 10 the upper edge 26a of the blocking member 26 en-

gages the second link arm 16 of one of the link joints to prevent movement of this arm out of its po- sition in substantially linear extension of the sec- ond link arm 16 of the other link joint.

In the non-blocking or released position in fig. 5 defined by abutment of the edge part 26c of the lower edge against the casing wall 10 the blocking member is disengaged from the second link arm 16 to allow movement of both link joints toward the unlocked po- sition shown in fig. 3.

The movement of the blocking member 26 between the blocking position and the released position may be effected as illustrated in figs. 6 and 7 by manual operation of a blocking operator 28 provided on the front side of the cover member 4. The blocking opera- tor 28 may as shown in fig. 6 be a relatively simple slide member that can be displaced by linear movement between two distinct positions corresponding to the blocking position and the released position, respec- tively, of the blocking member 26. As shown in fig. 7 the blocking operator 28 may be connected with the blocking member 26 through a flexible connecting mem- ber such as bowden-cable 28'extending partly through the cover member 4 in the longitudinal direction the- reof, partly through the ventilation passage.

In the alternative embodiment shown in figs. 8 and 9 the blocking mechanism comprises a cam member 29 connected with the actuator slide 13'guided in the guide track 14'for linear movement between first and second end positions via an intermediate position in the same way as explained above for the embodiment illustrated in figs. 1 to 7.

The plan view in fig. 8 shows part of the upper side of the base plate 9'of the casing of the lock- ing assembly and as illustrated the blocking mecha- nism further comprises a generally L-shaped blocking pawl member 30 arranged for movement about a station- ary pin 31 secured to the base plate 9'and engaging

curved circumferential edges of a mainly triangular cut-out 32 formed in the pawl member 30 to define re- spective end parts 33 and 34 engaging the pin 31 in a blocking position and a released position, respec- tively, of the pawl member 30 with respect to the cam member 29.

For engagement with an end part 35 of the cam mem- ber 29 having a substantially circular curvature in the above-mentioned second end position and the in- termediate position of the actuator slide 13'the pawl member 30 is formed in the side edge of a longer leg 36 facing the cam member 29 with a first engage- ment part 38 and in the corner between the longer leg 36 and the shorter leg 37 with a second engagement part 38, respectively, each with a curvature matching the curvature of the end part 35 of the cam member 29.

The pawl member 30 is biased towards engagement of the respective engagement parts 38 and 39 with the end part 35 of the cam member 29 by spring means com- prising a pressure spring 40 having one end secured to a stationary point 41 on the base plate 9', whereas the other end is connected with the pawl mem- ber 30 in a point of attack 42 substantially midway between the end parts 33 and 34 of the cut-out 32.

Thereby, in the second end position of the actua- tor slide 13', in which the pin 31 is engaged by the end part 33 of the cut-out 32 the spring force from pressure spring 40 will be transferred to the first engagement part 38 in the side edge of the longer leg 36 of the pawl member, whereas in the intermediate position of the actuator slide 13', in which the pin 31 is engaged by the end part 34 of the cut-out 32, the spring force from the pressure spring 40 is transferred to the second engagement part 39 at the corner between the longer and shorter legs 36 and 37.

In fig. 9 the respective positions of the cam mem- ber 29 and the blocking pawl member 30 in the second

end position and the intermediate position of the ac- tuator slide 13'corresponding to the closed position and the intermediate ventilating position of the co- ver member are shown at a) and b). As will appear, the engagement of cam member 29 with the second en- gagement part 39 provided at the corner between the longer and shorter legs 36 and 37 of the pawl member will prevent movement of the actuator slide 13'in the direction of release of the locking engagement between the movable pawl members and stationary lock- ing members of the locking assembly.

As illustrated at c) and d) in fig. 9, movement of the actuator slide 13'from the intermediate position shown at b) in the direction of release of the lock- ing engagement will be possible, however, by initial short movement of the actuator slide 13', by opera- tion of the cover member for the ventilation passage, in the direction towards the second end position shown at a). Thereby, the end part 35 of the cam mem- ber 29 will engage a projecting cam part 43 of the side edge of the longer leg 36 of the pawl member 30 between the first and second engagement parts 38 and 39 and the pawl member 30 will be displaced by move- ment in two directions with respect to the pin 31. In result, the cam member 29 may as shown at d) pass un- der the end of the shorter leg 37 of the pawl member 30.

As will appear from a), c) and d) in fig. 9 counter-clockwise pivotal movement of the pawl member 30 with respect to the pin 30 is limited by a sta- tionary pin 44 secured to the base plate 9'to be en- gaged by the side edge of the longer leg 36 facing away from the cam member 29, a recess 45 being formed in this side edge to enable a lifting movement of the pawl member 30 sufficient to allow passage of the cam member 29 under the shorter leg 37 of the pawl member 30.

Whereas the invention has been explained in the foregoing with reference to a locking assembly de- signed for manual operation of the cover member for the ventilation passage electrical operation of the blocking mechanism may easily be implemented both in the embodiment illustrated in figs. 1 to 7 and in the alternative embodiment shown in figs. 8 and 9.

Thus, in the embodiment of figs. 1 to 7 the piv- otal movement of the blocking member between the blocking position and the non-blocking position may be effected by use of a solenoid or a small electric motor as drive means connected with the blocking mem- ber by a suitable transmission.

In the alternative embodiment in figs. 8 and 9 the sequence of movements of the actuator slide may be effected by electrical operation of the cover member by means of a conventional electrical operator such as a chain operator, which can be programmed to im- plement the various phases of movement of the cover member and the actuator slide connected therewith.

In both cases, electrical operation of the block- ing mechanism may be accomplished by use of a remote control as well known in the art for control of the sash movement of a ventilating window.