Mounting hooks with variable hook width

Abstract

For the secure fastening of frames (9) suitable for fly screens and / or dust protection in the rebate (12) of window frames (11) with variable geometry, a hook (1) with variable hook width is proposed, which can be inserted into a mounting slot (10) in the frame (9) and clamps or locks into place there at various insertion depths. At least two clamping elements (3) acting as leaf springs, which have an antiparallel arrangement with opposing fixed ends (5) and freely springable ends (4), ensure that the clamping or locking force remains uniform over the depth of insertion into the mounting slot (10), thus allowing the hook width to be variably adapted to the geometry of the frame rebate (12).

Description

Field of invention The invention relates to a fastening hook, in particular for the simple, stable, secure and reversible fastening of frames intended for fly screens and / or dust nets in the frame rebate of window frames, which in particular has a variable hook width. To protect living spaces from insects, fine dust, sunlight, or pollen, protective materials and screens exist that can be designed and constructed as fly screens and / or dust nets. These consist of a frame suitable for fly screens and / or dust nets, covered with a sufficiently fine mesh or film, and then tightly attached all around the window or door opening. Ideally, they are attached to the frame – often also called the window frame. This allows the window sash to be opened for ventilation, for example, while the fly screen or pollen net continues to perform its protective function. Attaching the frame suitable for fly screens and / or dust nets to the window frame is regularly a technical challenge, as it must meet a number of requirements, including, for example: - simple installation and operation, so that even users without in-depth technical or craft knowledge can carry out the installation, - damage-free installation and trace-free removal, so that it can also be used in rented properties, for example, and - adaptability to different geometries and dimensions for installation in window frames of different manufacturers, designs and materials. State of the art A number of solutions are known in the prior art that meet these requirements, but also have significant disadvantages. From EP 1 596 034 B1, a support frame is known which can be fitted with a fly screen or pollen screen or the like and attached to a mounting frame that is mounted on an opening, such as a door or window opening. The support frame has profile beams that converge perpendicularly and can be connected by means of a corner connector. The support frame also has a connecting element made of a resilient material, in particular a resilient steel wire, with a first leg and a second leg, between the two inner ends of which a connection is provided, wherein at least the first leg of the connecting element has a retaining lug at its outer end. From EP 3 078 802 B1, a corner connector for an insect screen frame system with an angle element is known. The corner connector comprises a T-nut having an internal thread and a retaining clip held between this and a leg of the angle element by means of a screw connection, which projects beyond the leg of the angle element at its free end or end face. In the fastenings known from the above EP 1 596 034 B1 and EP 3 078 802 B1, elements made of spring steel wire protrude from the fly screen frame suspended in front of the window frame and engage behind a rebate of the window frame. The elasticity of the spring wire is used to adjust the clamping width to the width of the window frame rebate. The main disadvantage of this solution is the elastic flexibility of the fastening, meaning that even a relatively small force, which is regularly expected during normal use, can cause the frame to slip or even come loose. Furthermore, the round steel wire transfers the holding forces into the groove over a very narrow area, so that any weatherproof seal generally present there will be permanently deformed and damaged at a specific point after only a short time. Alternatively, hook elements made of bent sheet metal are commonly used. These are inserted into recesses in the fly screen frame and engage securely with the frame rebate of the window opening. These hooks are significantly stiffer and yield very little under force, exerting less surface pressure on the weatherproof seal, thus minimizing deformation and preventing damage. A disadvantage of this solution is that the hooks must be manufactured with a fixed hook width, and a single hook width cannot cover the entire range of typical frame rebate widths. Therefore, several sets of hooks in different hook widths must be included with every product placed on the market. This increases production costs, generates waste from unused hooks, and presents users with problems during installation when selecting the correct hook. Furthermore, with fixed-width hooks, it is difficult to generate the minimum contact pressure necessary for a complete seal between the facing and fly screen frames and / or dust screen frames. This design therefore requires more complex sealing elements between the facing and fly screen frames or dust screen frames, such as long-pile sealing brushes or elastic sealing lips with a high projection and deformability. Task The object of the present invention is therefore to produce a cost-effective and intuitively usable fastening solution in which the width of the hook elements can be varied over a wide range without them yielding significantly under normal force. Solution This problem is solved by the invention with the features of the independent claim. Advantageous embodiments of the invention are characterized in the dependent claims. The wording of all claims is hereby made explicit by reference to the content of this description. The invention also includes all meaningful and, in particular, all mentioned combinations of independent and / or dependent claims. The aforementioned problem is solved in particular by a fastening hook according to claim 1, which is designed such that the hook interacts in a suitable predetermined manner with a receiving geometry in the frame that is adapted to and corresponding with the hook. Apart from the application for fastening fly screen frames and / or dust net frames in window frames, hooks according to the invention can be used for a multitude of other fastening applications where a variable hook width is advantageous. According to the invention, the hooks are designed with at least one substantially rectangular hook tongue that can be inserted into a slot of a frame, particularly one intended for a fly screen and / or dust net, and there clamps and / or latches at a variable depth in a form-fit and / or force-fit manner corresponding to the geometry of the slot. For this purpose, the hook tongue of the hook is provided along its edges extending in the insertion direction with two elastically resilient, substantially beam-shaped clamping elements, each having a freely resilient end and an end rigidly connected to a central tongue element of the hook. The clamping elements can preferably be designed, in particular, to act as leaf spring clamping elements. The design, arrangement, and especially the restoring force of the spring-loaded clamping elements are used to clamp and / or lock the hook into a frame, particularly one designed as a fly screen frame and / or dust net frame, in a form-fit and / or force-fit manner corresponding to the geometry of the slot. The position of the free and fixed ends of the clamping elements is selected such that they lie at longitudinally opposite ends of the central tongue element of the hook tongue. The use of such spring-loaded, beam-shaped clamping elements is inherently disadvantageous because the restoring force of such a clamping element varies considerably depending on the insertion depth. The clamping force is minimal at the free end, increasing towards the fixed end, and no lateral deformation is possible directly at the fixed end. For example, if one or more such clamping elements were used in the same orientation, the hook would be very easy to insert and would develop only a small clamping force at shallow insertion depths. However, with increasing insertion depth, the force required for insertion, and the resulting clamping force in the receiving slot, would increase sharply and quickly exceed an acceptable range for the application.Additionally, the increasing deformation of the clamping element or elements would result in the outer edges of the tongue no longer being parallel, so that it would no longer be guided cleanly in the receiving slot. However, by means of an advantageous opposing or antiparallel arrangement of at least two spring-loaded clamping elements suitably arranged opposite each other on the hook tongue of the hook, uniform clamping or locking at different insertion depths can be achieved in a particularly simple and advantageous manner from a manufacturing perspective. This design utilizes the fact that the force curve of one clamping element, which increases in the insertion direction over the insertion depth, and the force curve of the other clamping element compensate each other. With a well-designed system, this results in a largely uniform distribution of insertion and clamping force across the entire insertion depth. Furthermore, this design and arrangement advantageously ensures continuous parallelism of the outer edges of the hook tongue, thus guaranteeing clean lateral guidance across the entire range of different insertion depths. In detail, when the hook tongue of such a hook is inserted into a suitable slot, the clamping element, whose free end lies at the tip of the hook tongue, yields, thus providing the necessary compliance for insertion and, through its restoring force, the necessary clamping and / or locking force. The second clamping element cannot yield at this insertion depth, as its fixed end is located there. As the insertion depth increases, the restoring force of the first clamping element also increases, but now the second clamping element can be elastically deformed, thus ensuring that the clamping force and / or locking force remains within an acceptable constant range over the entire insertion depth. The result is a mounting hook that can be manufactured cost-effectively using modern production methods. On the side of the frame, which is suitable as a fly screen frame and / or dust screen frame, only a slot of the appropriate height and width, corresponding to the mounting hook, is required. This keeps manufacturing costs low and allows for considerable design freedom, for example, regarding the number and position of the hooks. The frame can be manufactured, for instance, using plastic injection molding, as an extruded hollow profile, or as a sheet metal profile with simple punched, milled, laser-cut, or waterjet-cut slots in the profile wall. Such advantageously designed hooks can be easily inserted into the respective slots to attach a frame suitable as a fly screen frame and / or dust net frame, and after correct positioning of the frame in the window opening, can simply be pressed further in with normal hand force until the width suitable for a predetermined application is reached. In principle, hooks can be manufactured from any solid material, ideally with a sufficiently high yield strength, good spring properties, and low creep. For high holding force requirements, tempered spring steels are advantageous, while for cost-optimized injection-molded designs, processable plastics such as polyoxymethylene or short-fiber-reinforced polyamides are particularly suitable. A key advantage is that the entire hook can be manufactured from a single material or semi-finished product. For the manufacture of frames suitable as fly screen frames and / or dust net frames with the appropriate mounting geometry for the hooks, all solid materials are conceivable, such as aluminum or steel alloys, such as 38Si7, 46Si7, 55Cr3, 54SiCr6, 61 SiCr7 or 51 CrV4, as well as plastics, composite materials or wood. The fastening hook can be suitably designed in an angled shape, advantageously having two L-shaped legs, the legs being of different lengths and both being designed as hook tongues equipped with clamping elements. In this way, in situations where the insertion depth of the hook tongue in the frame is limited, a larger width range can be easily covered with just one hook. The shorter leg can be used for small hook widths, and the longer leg for larger ones. Alternatively, this design can provide two different overlaps of the hook with the window frame. Preferably, the long leg of the fastening hook has a length between 28 mm and 57 mm, while the short leg has a length between 17 mm and 39 mm. The width of the hook is preferably between 6 mm and 20 mm. The thickness of the fastening hook is preferably between 0.4 mm and 2 mm and is preferably at least four times smaller than the width of the fastening hook. The two legs of the angled L-shaped fastening hook can suitably form an angle in the range of at most 94°, preferably at most 90°, and advantageously 86° to 90°, and particularly advantageously about 88°, after which the hook can be inserted into the receiving slot particularly easily, especially up to its suitable insertion depth corresponding to the dimensions of the frame rebate, and wherein the correspondingly fully inserted hook is advantageously spaced with its apex from the frame rebate by a minimal amount of a few millimeters. The edge areas of the hook tongue's clamping elements, from which the clamping force is transferred to the inner wall of the slot in the frame, can be suitably provided with detent structures, each designed as a detent contour of external teeth, for positive and / or non-positive locking of the hook to the inner wall of the slot. Such a design, with a corresponding adaptation of the slot's inner geometry on the frame side, allows for a significantly higher pull-out force at a given clamping force, as well as an adjustable hook width in defined increments. The locking structures, particularly those designed as external teeth, can be suitably rounded so that the hook can be pushed in and pulled out without damaging the receiving geometry in the frame. This design is especially advantageous for all applications where the frame needs to be disassembled without damage. As an alternative to the locking structure described above, the locking structures can be suitably designed as barbs such that the hook can be pressed in but not easily pulled out of the receiving slot of a frame. This design is advantageous for applications where the highest possible pull-out force is required to securely hold heavy loads. A fastening hook according to the invention described above, with a variable hook width, is particularly suitable for the secure fastening of frames suitable for fly screens and / or dust protection in the rebate of window frames with variable geometry, wherein the hook is advantageously designed in such a way that it can be inserted into a receiving slot in the frame and can be easily, securely and reversibly wedged or locked in place at various insertion depths. The clamping elements of the hook tongue are suitably designed as leaf spring clamping elements which, as described above, have an advantageous antiparallel arrangement with opposing fixed ends and freely springing ends, so that the clamping or locking force of the clamping elements can remain uniformly advantageous and constant over the depth of insertion into the receiving slot, and thus the hook width can be easily and variably adapted to the geometry of the frame rebate. A fastening hook according to the invention as described above can preferably be designed as a one-piece fastening hook that holds a frame on the frame of a window, wherein the fastening hook can be inserted into the frame to a variable depth in order to adapt exactly to different frame thicknesses. As described above, the fastening hook suitably has clamping elements that develop an approximately equal clamping force at any insertion depth. By means of at least two clamping elements, acting in particular as leaf springs, which have an antiparallel arrangement with opposing fixed and freely springing ends, the clamping or locking force remains uniform over the depth of the insertion into the mounting slot and the hook width can be variably adjusted to the thickness of the frame rebate. The spring and locking force of the hook advantageously remains approximately constant regardless of the insertion depth into the mounting slot. A fastening hook according to the invention can be easily and adaptively adjusted to different frame geometries, thus eliminating the need to include hook sets of different sizes. A fastening hook according to the invention can advantageously be formed in one piece and manufactured simply and cost-effectively – for example, using suitable stamping and bending processes. Further details and features will become apparent from the following description of preferred embodiments in conjunction with the dependent claims. The respective features can be implemented individually or in combination with one another. The possibilities for solving the problem are not limited to the embodiments described. The exemplary embodiments are shown schematically in the figures. Identical reference numerals in the individual figures denote identical or functionally equivalent elements, or elements corresponding to each other with respect to their functions. Not all reference numerals are shown in all figures. Preferred embodiments of the hook and its interaction with the receiving geometry in the frame are shown by way of example. The illustrations are abstracted and limited to features essential to the invention. Specifically: Fig. 1 shows a schematic perspective view of a fastening hook according to one embodiment of the invention; Fig. 2 shows a top view of the fastening hook of Fig. 1 from a different perspective; Fig. 3 shows a side view of the fastening hook of Fig. 1; Fig. 4 shows a section of a frame suitable for a fly screen and / or a dust net together with the fastening hook of Fig. 1 in a first position; Fig.5A a longitudinal section of the frame of Fig. 4 with the mounting hook in a second position; Fig. 5B the frame of Fig. 5A with the mounting hook in a third position; Fig. 6 a cross-section of the frame with the mounting hook in a fourth position, mounted in front of a window frame; and Fig. 7 a cross-section of the frame with the mounting hook in a fifth position, mounted in front of a window frame. Fig. 1 shows a schematic perspective view of a fastening hook 1 according to one embodiment of the invention. The angled hook 1 is L-shaped with two legs 6, 7 of different lengths, each having a hook tongue 20. On each of the two legs 6, 7, adjacent to a central tongue element 2, opposing clamping elements 3 of the hook tongue 20 are provided, which have locking elements 8 arranged on their lateral edges. The locking elements 8 are suitably designed as tooth-like locking contours 8 such that an external toothing 8 is provided opposite the lateral edges of the hook 1. The clamping elements 3 differ in the arrangement and design of their respective freely spring-loaded ends 4 and fixed ends 5. The clamping element 3 shown on the right in the drawing is connected to the central tongue element 2 at the spaced-apart ends E of the two legs 6 and 7 of the hook tongue 20 and has a connection there to the central tongue element 2 of the hook tongue 20, designated as a corresponding fixed end 5. Furthermore, the clamping element 3 shown on the right in the drawing is also spaced apart from the central tongue element 2 in the region of the apex S of the angled L-shaped hook 1. The clamping element 3 shown on the left side of the drawing is connected to the central tongue element 2 of the hook tongue 20 in the region of the apex S of the angled L-shaped hook 1 and has a connection with the central tongue element 2 there, designated as a corresponding fixed end 5. At the spaced-apart ends E of the two legs 6 and 7 and the hook tongue 20, the clamping element 3 shown on the left side of the drawing is spaced from the central tongue element 2 and has an end E there, designated as a corresponding free end 4. In the fastening hook 1 according to the embodiment shown in Fig. 1, one clamping element 3, whose fixed end 5 is located at the end E of the hook tongue 20 spaced apart from the apex S, is connected at its free end 4 to the free end 4 of the corresponding clamping element 3 of the other hook leg 6, 7. This connection can increase the robustness of the hook 1, but is not functionally necessary. For the clamping elements 3, the free end 4 and the fixed end 5 are designated as such, as described above, so that the antiparallel orientation Re and Rs of the clamping elements 3 becomes clear. A suitable, predetermined insertion direction R of the hook 1 extends into a receiving slot 10 of a frame 9 suitable for a fly screen and / or dust net, as described below with reference to Fig. 4, from the apex S of the angled hook 1 to one of the spaced-apart ends E of the legs 6 and 7 and their hook tongues 20. While the direction Re of one of the clamping elements 3 from its fixed end 5 to its free end 4 coincides with the insertion direction R, the direction Rs of the other clamping element 3 from its fixed end 5 to its free end 4 is antiparallel to both direction R and direction Re. The two legs 6, 7 differ in length as described above. The short leg 6 has, for example, a six-toothed external toothing 8 on its opposite lateral edges, extending essentially from the apex S of the hook 1 to the exposed end E of the leg 6. Unlike the short leg 6, the long leg 7 has, for example, an eight-toothed external toothing 8 on the opposite lateral edges of its clamping elements 3, spaced from the apex S of the hook 1 and extending to the exposed end E of the leg 7. Otherwise, the contours of the external toothing 8 on the short leg 6 and long leg 7 are uniform. Fig. 2 shows a schematic representation of the fastening hook 1 of Fig. 1 in a top view of the long leg 7 with the tongue 20 of the hook 1, which illustrates the exact arrangement and design of the antiparallel clamping elements 3 each with their free ends 4 and their fixed ends 5 as well as the eight-toothed external toothing 8 and the directions R and Re and their antiparallel opposite direction Rs. Fig. 3 shows a schematic representation of the essentially L-shaped angled fastening hook 1 of Fig. 1 in a side view with the short leg 6 and the long leg 7. The two legs 6 and 7 suitably form an angle α in the range of at most 94°, preferably at most 90°, and advantageously an angle α in the range of 86° to 90°, and particularly advantageously about 88°. Fig. 4 shows the fastening hook 1 from Fig. 1 in a greatly reduced view, together with a section of a frame 9 suitable for fly screens and / or dust protection, and a slot 10 therein for receiving a hook tongue 20 of one of the two hook legs 6 and 7. The hook 1 is arranged in a first position P in front of the receiving slot 10, suitable for inserting the long hook leg 7 in the insertion direction R into the receiving slot 10. It is clear that the geometry of the receiving slot 10 and of the frame 9, with the design and dimensions of the hook 1, and in particular the hook leg 7, as well as the hook tongue 20 provided with the clamping elements 3 and the locking contours 8, are designed to correspond in a form-fit and / or force-fit manner such that the hook 1 can be reversibly inserted into the receiving slot 10, and the inserted hook 1 remains securely, stably, and firmly in its position. Fig. 5A shows a longitudinal section of the frame 9 of Fig. 4 at the level of the receiving slot 10 and the fastening hook 1 inserted therein in a second position Pmin of its minimum insertion depth and thus maximum hook width, wherein the hook 1 with its long hook leg 7 is inserted into the slot 10 up to the position Pmin, at which the clamping elements 3 with their outer contour 8 of the hook 1 just begin to interact with the inner contour of the slot 10 in a form-fit and / or force-fit manner. Fig. 5B, shown on the same drawing sheet in conjunction with Fig. 5A, depicts the frame 9 from Fig. 5A with the hook 1 in a third position Pmax, in which the clamping elements 3 of the hook 1, with their outer contour 8, still fully engage with the inner contour of the slot 10 in a form-fit and / or force-fit manner, and the hook 1 is inserted into the slot 10 to its maximum insertion depth, thus achieving a minimum hook width when this hook leg 7 is inserted. The hook 1 protrudes from the slot 10 and the frame 9 on both sides of the frame 9 by a predetermined amount, corresponding to its dimensions and the dimensions of the frame 9. Fig. 6 shows a cross-section of the frame 9 with the fastening hook 1 mounted in a fourth position P7 in front of a window frame 11. The diagram shows a cross-section of the frame 9 with the hook 1 inserted, passing through the receiving slot 10 and mounted in front of a window frame 11. It can be seen how the end E of the hook 1's short leg 6 rests against the rebate 12 of the frame 11 and holds the frame 9 in position. It is also evident that, in particular, the apex S of the hook 1 is slightly spaced away from the frame rebate 12, and that the tip of the long leg 7 of the hook 1, at the width of the frame rebate 12 shown, penetrates the frame 9 and protrudes on the opposite side. Position P7 essentially corresponds to that described above with reference to Fig.Position Pmax as described in 5B, in which the clamping elements 3 of the hook 1 with their outer contour 8 still fully interact with the inner contour of the slot 10 in a form-fit and force-fit manner, and the hook 1 is inserted into the slot 10 with its maximum insertion depth. Fig. 7, corresponding to Fig. 6 described above, shows a cross-section of the frame 9 with the fastening hook 1 mounted in a fifth position P6 in front of the window frame 11. Unlike Fig. 6, where the hook 1 is inserted with its long leg 7 into the slot 10 of the frame 9 up to position P7 or Pmax, in Fig. 7 the short leg 6 of the hook is inserted into the slot 10 of the frame 11 up to position P6, thus advantageously avoiding any protrusion of the hook 1 from the frame 9. Otherwise, the arrangement of the free end E of the long leg 7 of the hook 1, which rests against the frame rebate 12, and its apex S essentially corresponds to the arrangement of the end E of the short leg 6 of the hook 1 described above with reference to Fig. 6. Even though the figures show various aspects or features of the invention in combination, it is apparent to the person skilled in the art – unless otherwise stated – that the combinations shown and discussed are not the only possible ones. In particular, corresponding units or sets of features from different embodiments can be interchanged. Reference sign 1 Mounting hook, hook 2 Central tongue element 20 Hook tongue, tongue 3 Clamping element 4 Free end of the clamping element, free spring end of the clamping element 5 Fixed end of the clamping element 6 Short leg of the hook, hook leg 7 Long leg of the hook, hook leg 8 Detent element, detent contour, detent structure, external toothing 9 Fly screen frame, dust screen frame, frame 10 Mounting slot, mounting slot, slot 11 Window frame, frame 12 Frame rebate, rebate α Angle E End P, P6, Pmin, P7, Pmax Position R Direction, longitudinal direction, insertion direction Re, Rs Direction (antiparallel) S Vertex QUOTES INCLUDED IN THE DESCRIPTION This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature EP 1 596 034 B1 [0005, 0007] EP 3 078 802 B1 [0006, 0007]

Claims

Fastening hook (1) in particular for the simple, stable, secure and reversible fastening of frames (9) intended for fly screens and / or dust nets in the frame rebate (12) of window frames (11), characterized in that the fastening hook (1) has a variable hook width with the following features: - a substantially rectangular hook tongue (20) for insertion into a receiving slot (10) of a frame (9) and - at least two elastic clamping elements (3) each with a free end (4) and a fixed end (5), wherein the fixed ends (5) and free ends (4) of the clamping elements (3) are located on longitudinally opposite sides (R) of a central tongue element (2), and the clamping elements (3) together with the central tongue element (2) form the hook tongue (20) of the fastening hook (1). Fastening hook (1) according to claim 1, characterized in that the hook (1) is angled and has two L-shaped legs (6, 7) each with the hook tongue (20), wherein both legs (6, 7) have significantly different lengths. Fastening hook (1) according to claim 1 or 2, characterized in that the areas of the clamping elements (3) of the hook tongue (20) provided for contact with the receiving slot (10) have detent contours (8) which are designed and arranged in such a way as to create a detent, wherein the detent contours (8) are each designed and arranged as a detent contour of an external toothing (8), and the hook tongue (20) with in particular its clamping elements (3) is designed to be form-fit and / or force-fit corresponding with the geometry of the receiving slot (10). Fastening hook (1) according to claim 3, characterized in that the locking contours (8) have rounded transitions in both the insertion and withdrawal directions. Fastening hook (1) according to claim 3, characterized in that the locking contours (8) form barbs which are designed and arranged in such a way that they prevent movement of the hook (1) in the pull-out direction after the hook (1) has been inserted. Fastening hook (1) according to one of claims 2 to 5, characterized in that the long leg (7) of the hook (1) has a length of 28 mm to 57 mm, and the short leg (6) has a length of 17 mm to 39 mm, and the width of the hook (1) is preferably between 6 mm and 20 mm, and the thickness or material thickness of the hook (1) is preferably between 0.4 mm and 2 mm, and is preferably at least four times smaller than the width of the hook (1). Fastening hook (1) according to one of claims 2 to 6, characterized in that the two legs (6) and (7) of the angled L-shaped hook (1) form an angle (α) in the range of at most 94°, preferably at most 90° and advantageously 86° to 90° and particularly advantageously about 88°. Fastening hook (1) according to one of claims 2 to 7, characterized in that clamping elements (3) of the hook tongue (20) are provided opposite to each other on the two legs (6, 7) of the angle-shaped L-shaped hook (1) adjacent to the central tongue element (2). Fastening hook (1) according to one of claims 1 to 8, characterized in that the hook (1) is made of a solid material with a predetermined high yield strength, predetermined good spring properties and a predetermined low creep tendency, wherein the hook (1) is advantageously made of a material and / or a semi-finished product, and wherein the hook (1) is suitably made of a spring steel alloy or of a plastic that can be processed by injection molding, preferably polyoxymethylene or a short fiber reinforced polyamide. Fastening hook (1) according to one of claims 1 to 9, characterized in that the hook (1) with variable hook width is suitable for the secure fastening of frames (9) suitable for fly screens and / or dust protection in the rebate (12) of window frames (11) with variable geometry, wherein the hook (1) is designed such that it can be inserted into a receiving slot (10) in the frame (9) and clamps or locks there at different insertion depths. Fastening hook (1) according to one of claims 1 to 10, characterized in that the clamping elements (3) of the hook tongue (20) are designed as leaf spring clamping elements (3) which have an antiparallel arrangement with opposing fixed ends (5) and freely springable ends (4), so that the clamping or locking force of the clamping elements (3) remains uniform over the depth of the insertion into the receiving slot (10) and thus the hook width can be variably adapted to the geometry of the frame rebate (12). Use of a fastening hook (1) according to one of claims 1 to 11, characterized in that the hook (1) is used for a fastening task in which a variable width of the hook (1) is advantageous.

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