The casement windows nowadays available on the market are substantially realised with a frame to which a wing is coupled, that is equipped with arms to limit opening of the wing itself. Such known arms, that are of different types according to securing methods of arm to frame of window casing and/or wing, allow opening casement windows, where the wing is joined to its respective frame through common hinges, and slanting the wing inwards or outwards of the window, with different angles. Once having reached the desired slant, the arm locks the wing in such a position.

The currently marketed arms, however, have the following problems: if the wing assembly is not correctly performed, the block detaches by itself, providing a dangerous situation; in other cases, it is necessary to subject the profile to workings in order to be able to insert the arm, or the insertion occurs with a misaligned wing and therefore, once assembled, it is not possible any more to disassemble it.

Object of the present invention is solving the above prior-art problems, by providing an improved arm for a casement window wing that, though continuing to perform the function for which it is provided, can also be unhooked from the wing to allow a complete opening thereof, being an advantage for the end user, for example allowing him to clean the glasses.

The above and other objects and advantages of the invention, as will appear from the following description, are obtained by an improved arm for casement window wings as claimed in Claim 1.

Preferred embodiments and non-trivial variations of the present invention are claimed in the dependent Claims.

The present invention will be better described by some preferred embodiments thereof, given as a non-limiting example, with reference to the enclosed drawings, in which: -Figure 1 is a perspective view of a preferred embodiment of the improved arm according to the present invention; -Figure 2 is an exploded perspective view that points out the constructive parts of the arm in Fig. 1; -Figures 3 to 5 are respectively a side view, a top view and a perspective view of the arm in Fig. 1 coupled with a wing and in a lock position; and -Figures 6 to 8 are respectively a side view, a top view and a perspective view of the arm in Fig. 1 coupled with a wing and in an unlock position.

With reference to the Figures, a currently preferred embodiment of the improved arm 1 for casement window wings according to the present invention, is shown.

In such embodiment, the-improved arm 1 is commonly of an elongated shape and is substantially equipped with securing means 3 to the frame (not shown) and with securing means 7 to the wing 5, that cooperate with means 4 to limit the opening of wing 5.

In particular, the securing means 3 to the frame are here composed of a block 9, substantially shaped as a paralellepiped, further shaped in order to have engagement tabs 11 with the frame. The block 9, connected to the arm 1 with the help of washer 10, is used to fix the arm 1 to the window case frame, inserting the same into the raceways that are usually present in the frames and by tightening the dowels 13 placed in a slanted position. Once assembled, the block 9 is fixed and unmovable during use.

The means 4 for limiting the opening of wing 5 are composed of a foot shaped as a frustum of pyramid inserted into a raceway 25 of the wing 5 and tightened as abutting through the dowel 15: the foot 4 limits the sliding of securing means 7, thereby eventually limiting the opening of the wing 5 itself.

In turn, the securing means 7 to the wing 5 are composed of a connection device 17 that is sliding on the wing 5, and the device 17 is equipped with locking and unlocking means 19.

In particular, the sliding connection device 17 is composed of a block 17 equipped with a seat 20 for the connection to the wing, of a cylindrical pin 21 for securing to the arm 1 through a washer 22, and of a seat 23 for housing said locking and unlocking means 19 when locking.

In the preferred ambodiment shown, the locking and unlocking means 19 are made of resilient material and are composed of a wire spring 19 shaped in order to allow the manual actuation thereof. In fact, as in the example shown in the drawings, the wire spring 19 is shaped as a lifted appendix to be engaged by the user's hand fingers, in order to allow its hooking and unhooking from the locking and unlocking device 17 in the two operating positions.

Summarising, the arm 1 guarantees the connection between frame and wing 5, since it is secured through the means 7 that are movable and are slidingly inserted iunto the raceway 25, being usually present on the wings 5 of window cases. The spring 19 prevents the device 17 of the means 7 from rotating, thereby preventing the means 7 from unhooking from the wing 5. When instead the spring 19 is placed in the opening position, the rotation of the device 17 is allowed and it will therefore be possible to unhook the arm 1 from the wing 5 and obtain the complete opening of the wing 5.

The operation of the improved arm 1 according to the present invention will now be described, with particular reference to Figs. 3 to 8.

When the assembly of arm 1 is assembled on the wing 5 through the device 17, the wire spring 19 is in a straight position, like in Figs. 6 to 8. Once having inserted the device 17 into the raceway 25 being present in the wing 5, the means 7 are rotated, such means being composed of device 17 and spring 19, by about 90°, ideally lenghtwise aligning the means 7 with the raceway 25 of the wing 5, and then the spring 19 is closingly pushed towards the wing 5. The spring 19 will provide an occurred closure indication by being inserted into the suitable seat 23 obtained on the device 17, as shown in Figs. 3 to 5.

Under this locking condition, the device 17 can always rotate with respect to the arm 1, but it will always be roughly aligned with the raceway 25 of the wing 5 (with offset of only few degrees when aligning, according to the type of window case being used), thereby always guaranteeing the correct positioning of the device 17 and preventing undesired unhookings thereof.

In order to unhook the block from the wing, it will then be necessary to lift the spring 19 and to rotate the spring 19-device 17 assembly, thus allowing to unhook the arm 1 when it is necessary.

It must be noted that if the spring 19 is in an opening position and the device 17 is inserted into the raceway 25 to close the window case (without then lowering the spring 19 itself as previously mentioned), the position of the spring 19 will prevent the complete closure of the wing 5, thereby signaling that the assembly is not correct and thus guaranteeing a higher safety index.

Some preferred embodiments of the invention have been described, but obviously they are subjected to further modifications and variations within the same inventive idea. For example, it will be possible to provide the production of devices 17 and springs 19 with different shapes and dimensions according to the type of application and the type of window cases that are currently marketed, keeping unaltered the function of the means 7 of the present invention.