Improved inspection trapdoor

Abstract

An improved inspection trapdoor comprising: a fixed frame (TF), a movable frame (TM), a panel connected to the movable frame (TM), and connecting means (5, 6) for connecting the movable frame (TM) to the fixed frame (TF); wherein at least one of the frames (TM, TF) comprises at least three parts (1, 2), the ends (11, 21) of which are cut at 90 DEG, and at least three corner fittings (3, 4), each corner fitting connecting two adjacent parts (1, 2) in a transversely arranged arrangement; the corner fitting (3, 4) comprising a central portion (30, 40) adapted to abut against the ends (11, 21) of two adjacent components (1, 2) and two side inserts (31, 41) projecting from the central portion (30, 40) so as to couple with the components (1, 2); wherein the central portions (30, 40) of the corner pieces (3, 4) and the side inserts (31, 41) are made integrally.

Description

Technical Field

[0001] The present industrial utility model patent application relates to an improved inspection trapdoor. As is known, a trapdoor is usually installed at a position corresponding to an opening provided in a wall, thereby allowing inspection of a compartment arranged behind the wall. Background Art

[0002] It should be noted that in this specification the term "wall" refers indifferently to a vertical wall as well as a ceiling or a floor.

[0003] In order to better understand the problems and defects of the prior art, the trap door of the prior art is further described below in conjunction with the accompanying drawings defined as "prior art", wherein:

[0004] Figure 1 is a front view of a trap door according to the prior art;

[0005] Figure 2 yes Figure 1 Parts of the trapdoor's fixed frame and Figure 2 Schematic diagram of a section of a moving frame of a trap door, showing the discarded portion of the 45° cut;

[0006] Figure 2A is a schematic side view of two components placed one on top of the other;

[0007] Figure 2B yes Figure 2A A top view of two components; Figure 2B A 45° cut starting from one corner of the part is shown;

[0008] Figure 2C shows a side-by-side arrangement Figure 2B two parts of the body, not one above the other; Figure 2C shows a portion of an upper component and a portion of a lower component removed after a 45° cut, wherein these components are arranged one above the other;

[0009] Figure 3 and Figure 3A is a view of two trapdoors according to the prior art, wherein the components are connected by two different connection methods.

[0010] With reference to the above-mentioned figures, a conventional inspection trap door comprises:

[0011] - a fixing frame 91 adapted to be fixed to the wall corresponding to the opening of the wall;

[0012] - a movable frame 92, which is arranged inside the fixed frame 91 and can move between an open position and a closed position;

[0013] - a panel (not shown in the drawings) which is internally connected to the mobile frame 92; and

[0014] -Connection device( Figure 3 and Figure 3A ), which is used to movably connect and support the mobile frame 92 relative to the fixed frame 91.

[0015] Each frame 91 , 92 is composed of four parts 910 , 920 .

[0016] The end of each component 910, 920 is cut at 45° so that the end edge of the component 910, 920 coincides with and abuts the end edge of the component 910, 920 in the adjacent position.

[0017] according to Figure 3 In a first connection of the components shown, the connection between the two components 910, 920 is obtained by means of metal angle pieces 931, each comprising two wings, each wing being fixed to the components by means of screws 93v.

[0018] according to Figure 3A In the second connection mode of the parts shown, the connection between the two parts 910, 920 is obtained by metal corner pieces 932, each of which comprises two wings inserted into the longitudinal recesses of the two parts in adjacent positions. In this case, the connection of each wing to the corresponding part is obtained by stamping.

[0019] Although similar inspection trap doors have been widely accepted in the market to date, they obviously have some disadvantages.

[0020] The first disadvantage arises when cutting the component to size. In fact, cutting a component at 45° is an extremely complex and delicate operation and therefore very prone to errors.

[0021] Furthermore, the management of dimensional tolerances is extremely complex when the ends of the components are cut at 45°. More precisely, the trapdoors are not universal, that is, each external fixed frame 91 coincides with a single internal mobile frame 92, and therefore they are not interchangeable with each other. In other words, the mobile frames 92 are not interchangeable between inspection trapdoors of the same size, because there are minute defects that prevent interchangeability between mobile frames 92 of the same size.

[0022] Another disadvantage that impairs the inspection trap door according to the prior art relates to the waste of material during the manufacture of the components 910 , 920 .

[0023] In fact, according to the manufacturing process of the parts 910, 920, the parts are first provided and then the ends of the parts are cut at 45° according to the measurements previously calculated.

[0024] Cutting the component at a 45° angle will inevitably result in material waste, which typically ranges from a minimum of 5% to a maximum of 20%, depending on the size of the inspection trap to be made and the thickness of the component. Figure 2 In FIG. 1 , the portions of components 910 , 920 that are wasted are indicated by dashed lines.

[0025] In addition, due to the 45° cuts, operators cannot cut multiple overlapping parts of the same size at the same time.

[0026] By reference Figure 2A , Figure 2B and Figure 2C , such shortcomings will become more clear.

[0027] Generally, each component 910, 920 has vertical wings that do not allow the components to be perfectly stacked vertically, but rather create a staggered effect, such as Figure 2A shown. Figure 2A , two parts 910 ′, 910 ″ of the fixed frame 91 are shown, but the same applies to the parts of the mobile frame 92 .

[0028] This staggered arrangement of components 910', 910" does not allow a user to simultaneously cut components 910', 910" in the same manner in a single cutting operation.

[0029] For example, refer to Figure 2B and Figure 2C , when making a 45° cut starting from the edge S10' of the lower part 910', the lower part 910' will be cut correctly, while the upper part 910' will be cut at 45°, losing a portion t10' of the part that is proportional to the thickness of the vertical wing. The greater the thickness of the wing, the greater the portion t10" that the upper part loses relative to the lower part during the 45° cutting operation. The upper part 910" will therefore be shorter than the lower part 910".

[0030] Therefore, due to this inconvenience, it is necessary to cut one part at a time, so that it takes a long time to produce such an inspection trap door.

[0031] Such a long production time is very inconvenient in the mass production process of such inspection trapdoors.

[0032] Another disadvantage of the inspection trapdoor according to the prior art relates to the fact that, despite the precision and expertise of the operator during the assembly of the frames 91 , 92 , said frames often have steps (due to imperfect alignment of the components), which strongly affects the aesthetics of the finished trapdoor.

[0033] Furthermore, the corners of the inspection trap door have sharp edges which are extremely dangerous for the operator when mounting the inspection trap door on the wall.

[0034] WO2020120939A1 discloses a hatch, in particular for use in an opening on the floor of a building under construction. The hatch comprises an inner frame and an outer frame, wherein the inner frame is smaller than the opening and is inserted into the opening, and the outer frame is larger than the opening and rests on the floor. The hatch also comprises two door panels hinged to the outer frame and movable between a closed position and an open position.

[0035] Each frame comprises frame members defining a rectangular frame. Each frame member has a square or rectangular component and each lateral side is provided with a longitudinal channel extending over the entire length of the frame member. The frame members are cut at 90° at the ends so that their end faces are arranged orthogonal to the side faces.

[0036] The frame members of the frame are connected by a first glide element inserted into a channel of a frame member and a second glide element inserted into a channel of another frame member, the glide elements being coupled to each other by a threaded element.

[0037] Specifically, one of the two slide elements is provided with a threaded hole, and the other slide element is provided with a screw suitable for coupling with the threaded hole of the other slide element. In summary, in order to connect the two frame members, each slide element needs to be arranged near the end of the frame member so as to align the screw with the threaded hole. Then, with the help of a suitable tool such as a screwdriver, the screw is screwed into the threaded hole so as to engage the two slide elements and thus connect the two frame members.

[0038] The slideway elements coupled by means of threaded elements also serve to connect the inner frame to the outer frame.

[0039] This hatch is marred by a few shortcomings.

[0040] The assembly of the hatches, which are connected to the sliding elements by means of screw connections, is complex and time-consuming for the operator.

[0041] Furthermore, hatches are dangerous because the outer frame may have edges or protrusions that could injure an operator.

[0042] The existence of this edge or protrusion is due to the structural configuration of the frame, according to which at least four end faces of four frame members are exposed outwardly. In fact, the outwardly exposed end faces of the frame member may have burrs or sharp parts that may injure the user.

[0043] Furthermore, if the end faces are not completely flush with the sides of the adjacent frame members, an edge or step will be formed between the sides and the end faces, thus presenting a risk of injury to the operator.

[0044] DE202006004357U1 discloses a cover for a lighting and / or ventilation shaft. The cover comprises a frame with four rods and four connectors. Each connector connects two adjacent rods at 90°.

[0045] Each connector includes:

[0046] A square body with two channels arranged at right angles; two screws, each screw being inserted into one of the channels and engaging in a threaded seat arranged at the end of the rod.

[0047] Therefore, in order to connect two adjacent rods, it is necessary to place the two rods vertically, place the square body between the two rods, align the channel with the threaded seat, introduce the screw into the channel, and finally screw the screw into the threaded seat. Obviously, such an operation is quite complicated and slow to perform. Utility Model Content

[0048] The utility model aims to design an inspection trap door which is efficient, simple and has low manufacturing cost.

[0049] Another object of the invention is to design a trap door in which it is no longer necessary to cut the components at 45°.

[0050] Another object is to provide a trap door that is reliable and suitable for preventing injuries to the operator.

[0051] Therefore, the utility model provides an inspection trap door, comprising:

[0052] - a fixing frame suitable for fixing to a wall, corresponding to the opening of the wall;

[0053] - a mobile frame arranged inside the fixed frame;

[0054] - a panel connected to the mobile frame so as to close the opening; and

[0055] - connecting means for connecting the mobile frame to the fixed frame so that the mobile frame can be moved from an open position to a closed position,

[0056] wherein at least one of the frames comprises at least three components having ends cut at 90° and at least three corner pieces, wherein each corner piece connects two adjacent components in a transversely disposed arrangement;

[0057] The corner piece comprises: a central portion adapted to abut against the ends of two adjacent components; and two side inserts protruding from the central portion so as to be coupled with the components;

[0058] Its characteristics are:

[0059] The central portion of the corner piece and the side insert pieces are made in one piece. BRIEF DESCRIPTION OF THE DRAWINGS

[0060] For the sake of clarity, the inspection trap door according to the present invention is further described with reference to the accompanying drawings, which are of illustrative and non-limiting value only, in which:

[0061] Figure 1 is a front view of a trap door of the prior art;

[0062] Figure 2 is a schematic diagram of components of a fixed frame and components of a moving frame, showing portions of the components discarded after a 45° cut;

[0063] Figure 2A is a schematic side view of two components placed one on top of the other;

[0064] Figure 2B yes Figure 2A A top view of two components; Figure 2B A 45° cut from the edge of the part is shown;

[0065] Figure 2C yes Figure 2B A view in which two components are arranged side by side rather than one on top of the other; Figure 2C shows a portion of an upper component and a portion of a lower component removed after a 45° cut, wherein these components are arranged one above the other;

[0066] Figure 3 and Figure 3A is a view of two trap doors in the prior art, wherein the components are connected by two different connection methods;

[0067] Figure 4 is a front view of a trap door according to the utility model;

[0068] Figure 4A is an axonometric front view of a trap door according to the utility model;

[0069] Figure 5 is a rear view of the trap door according to the utility model;

[0070] Figure 5A is an axonometric rear view of a trap door according to the utility model;

[0071] Figure 6 It is a front axonometric schematic diagram of a corner piece of a movable frame of a trap door of the utility model;

[0072] Fig. 6A yes Figure 6 a view of the corner fitting shown;

[0073] Figure 7 It is a front axonometric schematic diagram of a corner piece of a fixed frame of a trap door of the utility model;

[0074] Fig. 7A yes Figure 7 a top view of the corner piece shown;

[0075] Figure 8 is an axonometric diagram of the components of the mobile frame;

[0076] Fig. 9 is a schematic axonometric view of the components of the fixed frame;

[0077] Fig.10 It is an enlarged schematic diagram of the connection method between the corner fitting and the component;

[0078] Fig. 10A It is a corner piece and Fig.10 A cross-sectional view of a component cut along the XX plane;

[0079] Fig.11 and Fig.11A are two rear axonometric views of the corner fittings of the fixed and mobile frames, in which the end stops and locking devices are provided;

[0080] Fig. 11B and Fig.11A Same, except provided with snap-on locking means connected to the corner piece of the fixed frame;

[0081] Fig. 11C and 11D are rear isometric views of the corner fittings of the fixed frame and the mobile frame, respectively, with end stops and locking devices provided therein;

[0082] Fig.12 An alternative version of the trap door according to the invention is shown. DETAILED DESCRIPTION

[0083] refer to Figures 4 to 11D , an inspection trap door according to the invention is described.

[0084] refer to Figure 4 , Figure 4A , Figure 5 and Figure 5A According to the utility model, the inspection trap door comprises:

[0085] - a frame TF suitable for being fixed to a wall, corresponding to an opening in the wall;

[0086] - a mobile frame TM arranged inside the fixed frame TF;

[0087] - a panel (not shown in the drawings) connected to the inside of the mobile frame TM so as to close the opening;

[0088] - connecting means 5, 6 for connecting the mobile frame TM to the fixed frame TF so that the mobile frame TM is movable between an open position, in which it is tilted relative to the fixed frame TF, and a closed position, in which it is located in the same plane as the fixed frame TF.

[0089] The trap door has a quadrilateral shape having four corners Q1, Q2, Q3 and Q4.

[0090] Specifically, the fixed frame TF includes four parts 2 whose ends 21 are cut at 90° and four corner pieces 4, each of which connects two parts 2 at adjacent positions. Similarly, the mobile frame TM includes: four parts 1, whose ends 11 are cut at 90°; and four corner pieces 3, each of which connects two parts 1 at adjacent positions.

[0091] refer to Figure 6 , Fig. 6A , Figure 7 and Fig. 7A Each corner piece 3, 4 comprises a central portion 30, 40 adapted to abut against said ends 11, 21 of two adjacent parts and two side inserts 31, 41 protruding from the central portion 30, 40 so as to be coupled with said parts 1, 2. Since the trapdoor has a square or rectangular shape, the two side inserts are orthogonal to each other and the two adjacent parts are orthogonal and arranged at right angles.

[0092] The central portion 30, 40 and the side insert pieces 31, 41 of each corner piece 3, 4 are integrally processed.

[0093] Preferably, the corner pieces 3, 4 are made of plastic material or die-cast aluminium or composite materials, such as polyamide PA6 loaded with glass and / or carbon fibres, or polyaramid (Kitan X).

[0094] Each corner piece 3, 4 and each part 1, 2 comprises a front surface adapted to be visible and a rear surface arranged opposite said front surface and adapted to face the compartment to be inspected.

[0095] The connection devices 5, 6 are configured to allow the mobile frame TM to swing relative to the fixed frame TF without causing the mobile frame TM to be detached from the fixed frame TF.

[0096] refer to Figure 5 and Figure 5A The connection devices 5, 6 are arranged on the corner pieces 3, 4 at two adjacent corners Q3, Q4 of the inspection trap door. The connection devices 5, 6 are arranged on the rear surfaces of the corner pieces 3, 4.

[0097] Each connecting device 5, 6 comprises two elements, namely:

[0098] a first element 6 having a first portion 61 integral with the corner piece 4 of the fixed frame TF and a second portion 62 covering and interfering with the corner piece 3 of the mobile frame TM;

[0099] A second element 5 having a first portion 51 integral with the corner piece 3 of the mobile frame TM and a second portion 52 covering and interfering with the corner piece 4 of the fixed frame TF.

[0100] Preferably, the second element 5 has a substantially L-shape, so that the two parts 51 and 52 of the second element 5 are perpendicular.

[0101] The two elements 5 and 6 operate in such a way that the two frames TM, TF never become disengaged, even when the mobile frame moves relative to the fixed frame.

[0102] refer to Figure 6 , Fig. 6A , Figure 7 and Fig. 7A The central part 30, 40 of each corner piece 3, 4 has a quadrilateral shape and includes two outer sides 302, 402 orthogonal to each other and two inner sides 301, 401 orthogonal to each other, and the side insert pieces 31, 41 protrude from the inner sides 301, 401, and the side insert pieces 31, 41 are in the shape of rectangular plates. Each insert piece 31, 41 has a recess 32, 42, in which a part of the components 1, 2 is coupled by deformation.

[0103] refer to Figure 7 and Fig. 7A The outer side 402 of the center part 40 of the corner piece 4 of the fixing frame TF is connected by a curved portion 40t, so that the outer side of the inspection trap door has no sharp edges. In this way, the inspection trap door does not pose a danger to the user when it is installed on the wall.

[0104] refer to Figure 8 and Fig. 9Each component 1 , 2 has a C-shaped cross section defining a longitudinal channel 10 , 20 extending over the entire length of the component 1 , 2 and opening at both ends 11 , 21 of the component.

[0105] Inserts 31, 41 are inserted into longitudinal channels 10, 20 from the ends 11, 21 of the parts, while the central parts 30, 40 remain outside the parts 1, 2, forming the corners of the frames TM, TF. The side inserts 31, 21 are fully inserted into the longitudinal channels 10, 20, so that the ends 11, 21 of the parts 1, 2 abut against the inside 301, 401 of the central parts 30, 40 of the corner pieces 3, 4.

[0106] Still reference Figure 8 and Fig. 9 Each component 1 , 2 comprises two opposite longitudinal tabs 18 , 28 which define a longitudinal channel 10 , 20 .

[0107] refer to Fig.10 and Fig. 10A In order to connect the inserts 31, 41 to the adjacent components 1, 2, it is first necessary to introduce the inserts 31, 41 into the longitudinal channels 10, 20 of the components 1, 2 (see Fig.10 ), the longitudinal tabs 18, 28 are then pressed so that they are deformed at at least one point to form a projection d which projects into the longitudinal channels 10, 20 and couples with the recesses 32, 42 of the side inserts 31, 41 (see Fig. 10A ).

[0108] refer to Figure 6 and Fig. 6A , the central part 30 of the corner piece 3 of the mobile frame TM comprises two retaining edges 35 arranged on two outer sides 302 of the central part 30 .

[0109] refer to Figure 7 and Fig. 7A The central part 40 of the corner piece 4 of the fixed frame TF comprises two uprights 45 , which are perpendicular to each other and are arranged corresponding to the angle defined by the two inner sides 401 of the central part 40 .

[0110] Back to Figure 8 and Fig. 9 , each component 1, 2 preferably comprises two wings orthogonal to each other, namely:

[0111] a first wing 14, 24 having a C-shaped cross section and having said longitudinal channel 10, 20; and

[0112] A second wing 15 , 25 which projects from one side of said first wing 14 , 24 in an opposite direction relative to the longitudinal channel 10 , 20 .

[0113] The second wings 15 of the parts 1 of the mobile frame TM are arranged side by side and abut against the retaining edges 35 of the center part 30 of the corner piece 3 of the mobile frame TM, so that all the retaining edges 35 and the second wings 15 of the parts 1 of the mobile frame TM define a single outer annular edge of the mobile frame TM.

[0114] Preferably, the height of the second wing 15 of the part 1 of the mobile frame TM is the same as the height of the retaining edge 35 so that the top edges of the second wing 15 and the retaining edge 35 at adjacent positions are flush with each other.

[0115] The second wings 25 of the parts 2 of the fixed frame TF are arranged side by side and abut the adjacent uprights 45 of the central part 40 of the corner piece 4 of the fixed frame TF so that the uprights 45 and the second wings 25 of the parts 2 of the fixed frame TF define a single inner annular edge of the fixed frame TF.

[0116] Preferably, the height of the second wing 25 of the part 2 of the fixing frame TF is the same as the height of the pillar 45 , so that the top edges of the second wing 25 and the adjacent pillar 45 are flush with each other.

[0117] Back to Figure 5 and Figure 6 End stop devices 70, 71, 72 are provided corresponding to the corners Q1, Q2 opposite to the corners Q3, Q4 provided with the connecting devices 5, 6, and the end stop devices 70, 71, 72 are suitable for stopping the travel of the moving frame TM when the moving frame TM moves from the closed position to the open position.

[0118] The end stoppers 70 , 71 , 72 are disposed between two adjacent corner pieces 3 , 4 of the mobile frame and the fixed frame, corresponding to the rear surfaces of the corner pieces 3 , 4 .

[0119] refer to Fig.11 , the end stop devices 70, 71, 72 include:

[0120] - a first eyelet 71 connected to the corner piece 4 of the fixing frame TF;

[0121] - a second eyelet 72 connected to the corner piece 3 of the mobile frame TM; and

[0122] A chain 70 connected on one side to the first eyelet 72 and on the other side to the second eyelet 72 .

[0123] The chain 70 includes two hooks (specifically two spring hooks), one of which is fastened to the first eyelet 71 and the other of which is fastened to the second eyelet 72 .

[0124] Furthermore, the chain 70 includes a line connected to two hooks.

[0125] Advantageously, said first eyelet 71 is formed in one piece with the corner piece 4 of the fixed frame TF and said second eyelet 72 is formed in one piece with the corner piece 3 of the mobile frame TM.

[0126] refer to Figure 5 , Fig.11 , Fig.11A , Fig. 11B , Fig. 11C and Fig.11D , corresponding to the corners Q1, Q2 provided with the end stoppers 70, 71, 72, locking devices 81, 83 are provided to stop the mobile frame TM in the closed position relative to the fixed frame TF. In addition, the locking devices 81, 83 are provided corresponding to the rear surfaces of the corner pieces 3, 4.

[0127] The locking devices 81, 83 include:

[0128] - a retaining element 81 integral with the corner piece 3 of the mobile frame TM and configured so as to define a recess 82 in the undercut;

[0129] - snap-fit ​​retaining means 83, which only Fig. 11B , which is integral with the fixed angle piece 4; the snap-fit ​​retaining device 83 comprises a fixed portion 831 and a movable portion 832, the movable portion 832 is hinged to the fixed portion 831, and the movable portion 832 is provided with a striker 830 suitable for engaging in the undercut recess 82.

[0130] Preferably, the retaining element 81 is formed in one piece with the corner piece 3 of the mobile frame TM.

[0131] The snap-fit ​​retaining device 83 comprises a retaining device (not shown in the drawings) connected on one side to a fixed part 831 and on the other side to a mobile part 832, which operates on the mobile part 832 so that the striker 830 engages in a recess 82 in the undercut when the mobile frame TM is in the closed position, allowing the mobile frame TM to be moved away from the closed position when the mobile frame TM is pushed to the open position by the user with a force sufficient to overcome the resistance provided by the retaining device. For example, the retaining device can be composed of a torsion spring, one end of which is connected to the mobile part 832 of the snap-fit ​​retaining device 83 and one end is connected to the fixed part 831 of the snap-fit ​​retaining device 83.

[0132] It is therefore self-evident that in order to move the Moving Frame TM from the closed position to the open position, the Moving Frame TM (or the central panel) needs to be pushed with sufficient force to overcome the resistance provided by the retaining means, thereby disengaging the striker 830 from the notch 82 in the undercut.

[0133] refer to Fig.11 , Fig.11A , Fig. 11B and Fig.11D , said snap-fit ​​retaining means 83 are mounted on a supporting element 85 formed in one piece with the corner piece 4 of the fixed frame TF.

[0134] Said support element 85 consists of a wall protruding orthogonally from the rear surface of the corner piece 4 of the fixing frame TF and comprises an inner surface 851 facing the inside of the trapdoor, an outer surface 852 facing the opposite side, and two side surfaces 853. The inner surface 851 is provided with a recess which is suitably configured to accommodate the snap-fit ​​retaining device 83. The fixing portion 831 of the snap-fit ​​retaining device 83 is fixed to the support element 85 by means of a fixing screw FF which is inserted into a hole of the fixing portion 831 and engages in a hole sw drilled in the support element 85.

[0135] The base of the support element 85 is provided with a groove 86 into which the tab 28 of one of the parts 2 of the fixing frame TF is inserted.

[0136] Preferably, the first eyelet 71 is formed on the side surface 853 of the support wall 85, and the second eyelet 72 is formed on one of the inserts 31 of the corner piece 3 of the mobile frame TM.

[0137] Reference again Figures 11 to 11D The reinforcing bulkheads uf, um are preferably provided on the rear surface of each corner piece 3, 4 and straddle between the central portion 30, 40 and the insert 31, 41.

[0138] Through the above description, the advantages of the utility model become obvious. The advantages are as follows:

[0139] - less waste or scrap compared to the prior art; in particular, in the inspection trap according to the invention, virtually no waste or scrap is generated during the cutting of the components, since it is no longer necessary to cut the ends of the components at 45°;

[0140] - dimensional tolerances are easily manageable; more precisely, due to the 90° cuts of the ends 11 , 21 of the parts 1 , 2 , trapdoors of the same size are identical; therefore, if more than one inspection trapdoor of the same size is installed, the mobile frame TM is interchangeable;

[0141] - Higher safety compared to prior art inspection traps, due to the absence of sharp edges on the outside of the fixing frame TF;

[0142] - a highly flexible design, which means that the corner pieces 3, 4 can be made of plastic material or of die-cast aluminium; in both cases, a simple modification of the moulds used for production makes it possible to adapt them to any variation of the trapdoor;

[0143] - more aesthetically pleasing compared to the trapdoors of the prior art; in fact, the parts 1, 2 and the corner pieces 3, 4 are perfectly aligned, so that, unlike the prior art, the frames TM, TF do not have steps which, besides being aesthetically unpleasing, are extremely dangerous for the operator;

[0144] - Furthermore, the 90° cut allows cutting simultaneously, in the same way and with the same dimensions, several parts arranged one on top of another; the possibility of cutting simultaneously several parts placed one on top of another makes the manufacture of the trapdoor according to the invention much faster than trapdoors of the prior art.

[0145] Further, when the inspection trap door according to the utility model is compared with the trap door disclosed in WO2020120939A1 and DE202006004357U1, the inspection trap door of the utility model is:

[0146] - Easier to assemble than the other two trapdoors, since it does not require the use of screws or the joining of multiple elements and only requires the joining of the corner pieces 3, 4 formed in one piece with the two adjacent parts 1, 2;

[0147] - more versatile than the other two trapdoors, since the corner pieces 3, 4 formed in one piece can be provided with functional elements such as the connecting means 5, 6, the locking means 81, 83 and the eyelets 71, 72 of the end stops;

[0148] - Safer than the trapdoor disclosed in WO2020120939A1 because the ends of the components 11, 21 (the parts of the components that may have burrs or defects due to cutting) abut against the inner sides 301, 401 of the central parts 30, 40 of the corner pieces 3, 4 and are therefore not visible or exposed, and there is no risk that the user may touch them or come into contact with them, causing injury or cuts.

[0149] Numerous variations and detailed modifications may be made to the present embodiments of the invention within the capabilities of those skilled in the art, but within the scope of the invention as expressed in the appended claims.

[0150] For example, although the trapdoor is shown as having a quadrilateral shape, the trapdoor may have any other shape, such as a triangle, a pentagon, a hexagon, etc.

[0151] In the case of a triangular shape, each frame TM, TF will have three parts 1, 2 with ends 11, 21 cut at 90° and three corner pieces 3, 4. In this case, each corner piece will connect two adjacent parts 1, 2 in an arrangement where the two parts 1, 2 are transverse to each other, but not orthogonal.

[0152] Finally, although Figures 4 to 11D A trapdoor is shown with a fixed frame TF and a mobile frame TM made of parts and corner pieces, but if the mobile frame is not made of parts and corner pieces but is made in one piece with the central panel, defining a single integral cover door E that swings relative to the fixed frame TF, there will be no change in achieving the objectives pursued by the invention. This alternative version is as Fig.12 shown.

Claims

1. Check the trap door, including: - a fixing frame (TF) suitable for being fixed to the wall, corresponding to the opening of the wall; - a mobile frame (TM) arranged inside the fixed frame (TF); - a panel connected to said mobile frame (TM) so as to close said opening; and - connecting means (5, 6) for connecting the mobile frame (TM) to the fixed frame (TF) so as to enable the mobile frame (TM) to be moved from an open position to a closed position, wherein at least one of the frames (TM, TF) comprises at least three components (1, 2) having ends (11, 21) cut at 90° and at least three corner pieces (3, 4), wherein each corner piece connects two adjacent components (1, 2) in a transversely arranged arrangement; The corner piece (3, 4) comprises: a central part (30, 40) adapted to abut against the ends (11, 21) of two adjacent parts (1, 2); and two side inserts (31, 41) protruding from the central part (30, 40) so as to be coupled to the parts (1, 2); Its characteristics are: The central portion (30, 40) and the side insert (31, 41) of the corner piece (3, 4) are made in one piece.

2. The inspection trap door according to claim 1, characterized in that: The fixed frame (TF) comprises four parts (2) and four corner pieces (4); each corner piece (4) of the fixed frame (TF) connects two adjacent parts (2); wherein each corner piece (3, 4) has the side insert (31, 41) in a vertical position.

3. The inspection trap door according to claim 1, characterized in that: The corner pieces (3, 4) are made of plastic material or die-cast aluminum or composite material.

4. The inspection trap door according to claim 1, characterized in that: The side inserts (31, 41) of the corner pieces (3, 4) are in the shape of rectangular plates.

5. The inspection trap door according to claim 1, characterized in that: Each side insert piece (31, 41) has a recess (32, 42) in which a portion of the components (1, 2) is coupled by deformation.

6. The inspection trap door according to claim 1, characterized in that: Each component (1, 2) has a C-shaped cross section defining a longitudinal channel (10, 20) opening at the end (11, 21) of the component; the insert (31, 41) of the corner piece (3, 4) is inserted into the longitudinal channel (10, 20) of the component (1, 2) from the end of the component.

7. The inspection trap door according to claim 6, characterized in that: The longitudinal channel (10, 20) of the component is defined by two opposing tabs (18, 28), wherein each longitudinal tab (18, 28) is deformed to define a projection (d) which projects within the longitudinal channel (10, 20) to couple with the recess (32, 42) of the side insert (31, 41) of the corner piece (3, 4).

8. The inspection trap door according to claim 1, characterized in that: The central part (30, 40) of the corner piece (3, 4) has a quadrilateral shape and comprises two outer sides (302, 402) and two inner sides (301, 401), which are provided with the insert (31, 41) arranged in a protruding position; the central part (30, 40) is located outside the part (1, 2) so as to form the corner of the frame (TM, TF).

9. The inspection trap door according to claim 8, characterized in that: The outer side (402) of the central portion (40) of the corner piece (4) of the fixing frame (TF) is connected by a curved portion (40t), so that the outer side of the inspection trap door has no sharp edges.

10. The inspection trap door according to claim 1, characterized in that: A locking device (81, 83) is included, which is suitably configured to lock the mobile frame (TM) in the closed position relative to the fixed frame (TF).

11. The inspection trap door according to claim 10, characterized in that: The locking devices (81, 83) are arranged on the corner pieces (3, 4) located corresponding to the two adjacent corners (Q1, Q2) of the trap door.

12. The inspection trap door according to claim 10, characterized in that: The connecting devices (5, 6) are arranged on the corner pieces (3, 4) located corresponding to the two adjacent corners (Q3, A4) of the trap door.

13. The inspection trap door according to claim 10, characterized in that: The locking device (81, 83) comprises: - a retaining element (81) formed integrally with the corner piece (3) of the mobile frame (TM); said retaining element (1) being configured to define a recess (82) in the undercut; - a snap-fit ​​retaining device (83) formed integrally with the corner piece (4) of the fixed frame (TF); the snap-fit ​​retaining device (83) comprises a fixed part (831) and a movable part (832), the movable part (832) being hinged to the fixed part (831) and having a striker (830) suitable for being accommodated in the recess (82) in the undercut.

14. The inspection trap door according to claim 13, characterized in that: The retaining element (81) is formed as one piece with the corner piece (3) of the mobile frame (TM); the locking device (3) is mounted on a supporting element (85) which is formed as one piece with the corner piece (4) of the fixed frame (TF).

15. The inspection trap door according to claim 1, characterized in that: The invention comprises a stop device (71, 72, 73), wherein the stop device (71, 72, 73) is arranged between the corner piece (3) of the movable frame (TM) and the corner piece (4) of the fixed frame (TF), and is suitable for stopping the travel of the movable frame (TM) when the movable frame (TM) moves from the closed position to the open position.

16. The inspection trap door according to claim 15, characterized in that: The stopping device (71, 72, 73) comprises: - a first eyelet (71) connected to the corner piece (4) of the fixing frame (TF); - a second eyelet (72) connected to the corner piece (3) of the mobile frame (TM); and - a chain (70) connected on one side to the first eyelet (72) and on the other side to the second eyelet (72).

17. The inspection trap door according to claim 16, characterized in that: The first eyelet (71) is made integrally with the corner piece (4) of the fixed frame (TF), and the second eyelet (72) is made integrally with the corner piece (3) of the mobile frame (TM).

18. The inspection trap door according to claim 1, characterized in that: The connecting device (5, 6) comprises: a first element (6) having a first portion (61) formed integrally with the corner piece (4) of the fixed frame (TF) and a second portion (62) covering the corner piece (3) of the mobile frame (TM) and interfering with the corner piece (3) of the mobile frame (TM); A second element (5) having a first portion (51) formed integrally with the corner piece (3) of the mobile frame (TM) and a second portion (52) covering the corner piece (4) of the fixed frame (TF) and interfering with the corner piece (4) of the fixed frame (TF).

19. Inspection trap door according to any one of claims 6 to 18, characterized in that Each component (1, 2) comprises two wings in orthogonal positions, namely: - a first wing (14, 24) having a C-shaped cross section and having said longitudinal channel (10, 20); and - a second wing (15, 25) which projects from one side of the first wing (14, 24) in an opposite direction relative to the longitudinal channel (10, 20).

20. The inspection trap door according to claim 19, characterized in that: The central part (30) of the corner piece (3) of the mobile frame (TM) comprises two retaining edges (35) arranged on two outer sides (302) of the central part (30), wherein the second wing (15) of the component (1) of the mobile frame (TM) is arranged side by side and adjacent to the retaining edge (35) of the central part (30) of the corner piece (3) of the mobile frame (TM), so that all the retaining edges (35) and the second wing (15) of the component (1) of the mobile frame (TM) define a single outer annular edge of the mobile frame (TM).

21. The inspection trap door according to claim 20, characterized in that: The height of the second wing (15) of the part (1) of the mobile frame (TM) is the same as the height of the retaining edge (35), so that the top edges of the second wing (15) and the adjacent retaining edge (35) are flush with each other.

22. Inspection trap door according to claim 1 or any one of claims 3 to 10, characterized in that The mobile frame (TM) and the panel are made in one piece, defining a single cover door (E).

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