Method for fixing a ladder and its locking member

Abstract

The present invention aims to provide a technology for securing ladders to ensure safety, from household use such as cleaning high places and inspecting roofs and gutters, to professional use such as working at heights on construction sites, by preventing the ladder from wobbling. [Solution] A method for fixing a ladder to a building, comprising a first fixing means and a second fixing means, the first fixing means comprising an installation step of installing screw members into the walls on both sides of the ladder's support columns and a tensioning step of stretching a rope or wire through the ladder's steps using a ratchet-type load securing device to the screw members installed in the installation step, the second fixing means comprising a locking member holding step of attaching a locking member to the window frame of the building to hold the ladder to the window frame, the locking member comprising a set of roughly gate-shaped frames connected by a connecting member and having an indoor locking part and an outdoor locking part, the window frame and the ladder are sandwiched between the roughly gate-shaped frames and the locking member is provided with a length adjustment mechanism that allows the length of the locking member to be adjusted in the direction corresponding to the thickness dimension of the window frame.

Description

Technical Field

[0001] The present invention relates to a method for fixing a ladder and a locking member thereof. Specifically, when an operator performs work at a height during building exterior wall or roof repair, etc., it is a method to prevent the ladder from moving back and forth, left and right. By implanting an anchor bolt and attaching a locking member to the window frame, it relates to a technique for ensuring safe work.

Background Art

[0002] The number of falling accidents from ladders in industrial accidents in the construction industry is on the increase, and their safety must be ensured. The Industrial Safety and Health Regulations, etc. specify in detail the fixing means of ladders. However, in minor exterior wall painting of ordinary houses or rooftop work such as antennas, falling accidents, etc. occur without taking fixing measures. As requirements for ladders, it is stipulated that they should have a strong structure, no significant damage or corrosion, a width of 30 cm or more, and the installation of an anti-slip device and other anti-displacement measures, but specific anti-displacement measures are not shown. As a measure to prevent falling from a ladder, there is a method of having an assistant support it, but even if the lower part is supported, the upper part cannot be supported and safety cannot be ensured. It is safe if a scaffold is assembled, but it is costly. Therefore, as a method for preventing falling from a ladder, a technical proposal for a simple and cost-effective ladder fixing method is required.

[0003] In light of the aforementioned problems, various technologies have been proposed in the past. For example, a technology titled "Evacuation Ladder Device" has been made public and is considered publicly known technology (see Patent Document 1). Specifically, the objective is to "provide an evacuation ladder device that is significantly more compact and easier to handle when stored, while ensuring sufficient safety when extended for use." The solution is to "provide a telescopic ladder body 2 that can be changed between a shortened storage state and an extended use state by sequentially connecting multiple basic members 7 consisting of a pair of parallel cylindrical support bodies 11 and a horizontal rung 12 so that each cylindrical support body 11 can slide against each other; an extension speed control means 3 that can control the extension speed when the ladder body 2 in the shortened storage state is changed to the extended use state by gravity when it is in a vertical or nearly vertical position; a fastener 4 that is attached to the uppermost basic member 7a and can be hooked onto a protruding fixing part 27 of a building such as a window frame; an extension handrail member 5 that is housed in the cylindrical support body 11a of the uppermost basic member 7a so as to be able to be pulled upward; and a locking mechanism 6 that can fix and release the extension handrail member 5 to the cylindrical support body 11 when it is pulled upward." The invention described in Patent Document 1 is a technology used in an evacuation ladder with retractable support columns, and involves fixing a locking device to the top. This differs from the present invention, which involves attaching a locking device to an existing non-retractable ladder used for high-altitude work at construction sites, etc., in order to solve a different problem.

[0004] Furthermore, there is a technology called "Ladder with Side-Tipping Prevention" (see Patent Document 2). Specifically, the problem is to "prevent a long ladder from tipping sideways or backward by attaching ropes and wire ropes and tying them to a stake or fixed object, allowing one to climb to high places safely and work safely even without someone supporting it from below," and the solution is to "attach ropes and wire ropes (2) to the ladder (1), and tie the ends of the ropes and wire ropes (2) to a stake or fixed object (3) to fix the ladder so that it does not tip sideways or backward." However, although the problem to be solved is similar to that of the present invention, the method of fixing the ladder uses ropes and wires, but there is no tension on them, and it must be said that it is difficult to ensure safety during work.

[0005] Furthermore, there is a technology whose invention is titled "Ladder Anti-Slip Device" (see Patent Document 3). Specifically, it addresses the problem that "when an aluminum two-step ladder is used in a two-story house, it reaches a considerable height, and because there are PVC rain gutters at the eaves of the roof or the roof is sloped, it is leaned against a roof section that feels dangerous, making it slippery and dangerous." The solution is to "set a ladder anti-slip device on the top of the aluminum ladder, extend a wire rope 1 and fix it to the target workpiece, connecting the workpiece and the ladder and fixing the top of the ladder." However, although the problem that the invention described in Patent Document 3 aims to solve is similar to that of the present invention, it differs from the present invention in that the fixing point of the ladder is only the top and the shape of the locking device. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Publication No. 2011-74749 [Patent Document 2] Japanese Utility Model Publication No. 5-78900 [Patent Document 3] Japanese Patent Publication No. 2001-254582 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] The present invention aims to provide a technology for securing ladders to ensure safety, from household use such as cleaning high places and inspecting roofs and gutters, to professional use such as working at heights on construction sites, by preventing the ladder from wobbling. [Means for solving the problem]

[0008] The present invention relates to a method for fixing a ladder to a building, comprising a first fixing means and a second fixing means, wherein the first fixing means comprises an installation step of installing screw members into the walls on both sides of the ladder's support columns, and a tensioning step of stretching a rope or wire through the ladder's steps using a ratchet-type cargo securing device to the screw members installed in the installation step, wherein the second fixing means comprises a locking member holding step of attaching a ladder fixing locking member to the window frame of the building to hold the ladder to the window frame, wherein the ladder fixing locking member comprises two sets of substantially gate-shaped frames connected by a connecting member, comprising an indoor locking part and an outdoor locking part, the window frame and the ladder are sandwiched between the substantially gate-shaped frames, and the length adjustment mechanism is provided to allow the length of the locking member to be adjusted in the direction corresponding to the thickness dimension of the window frame.

[0009] Furthermore, the present invention may also adopt a configuration in the first fixing means that includes an installation step of installing screw members into the walls on both sides of the ladder support columns, and a tensioning step of tensioning ropes or wires to the screw members installed in the installation step using ratchet-type load securing devices positioned on the left and right sides via the steps of the ladder.

[0010] Furthermore, the present invention relates to a ladder fixing locking member for fixing a ladder used in a second fixing means of a ladder fixing method according to claim 1 or claim 2, wherein the ladder fixing locking member may also be configured such that two sets of substantially gate-shaped frames are connected by a connecting member to form an indoor locking portion and an outdoor locking portion, the window frame and the ladder are sandwiched between the indoor locking portion and the outdoor locking portion, and the length of the locking member can be adjusted in the direction corresponding to the thickness direction of the window frame.

[0011] Furthermore, the present invention may also adopt a configuration in which the locking member for fixing the ladder is equipped with a clamping force assisting mechanism for increasing the clamping force when the ladder is clamped by the substantially gate-shaped frame. [Effects of the Invention]

[0012] The ladder fixing method and locking member according to the present invention provides the excellent effect of securely fixing the ladder by applying a first fixing means near the tip of the leaning ladder and locking it with a locking member near the middle.

[0013] Furthermore, the ladder fixing method and locking member according to the present invention offer the excellent advantage of allowing existing ladders to be used as they are, without requiring any processing.

[0014] Furthermore, the ladder fixing method and locking member according to the present invention have the excellent effect of being suitable for mass production because their simple structure reduces manufacturing costs. [Brief explanation of the drawing]

[0015] [Figure 1] This is a diagram illustrating the basic steps of the ladder fixing method according to the present invention. [Figure 2] This is an explanatory diagram of the configuration of the first fixing means, showing the configuration of the fixing device used in the first fixing means in the ladder fixing method according to the present invention. [Figure 3]This is an explanatory diagram of the configuration of the second fixing means, showing the configuration of the locking member used in the second fixing means in the ladder fixing method according to the present invention. [Figure 4] This is an explanatory perspective view showing the arrangement of the locking member used in the second fixing means of the ladder fixing method according to the present invention, in which it is placed on a window frame. [Figure 5] This is an explanatory diagram showing the arrangement of the fastener used in the first fastening means and the locking member used in the second fastening means in the ladder fastening method according to the present invention, arranged on a window frame. [Figure 6] This is an explanatory diagram illustrating another arrangement of the fastener used in the first fastening means and the locking member used in the second fastening means in the ladder fastening method according to the present invention, arranged on a window frame. [Modes for carrying out the invention]

[0016] The method for fixing a ladder and its locking member according to the present invention is a method for fixing a ladder H to a building T, which comprises a first fixing means A and a second fixing means B. The first fixing means A includes a planting step C of implanting a screwing member 10 into walls K on both sides of a support F of the ladder H, and a tensioning step D1 of tensioning a rope or wire 11 to a ratchet type clamping machine 20 through a step portion S of the ladder H with respect to the screwing member 10 implanted in the planting step C. The second fixing means B includes a locking member holding step E of attaching a locking member 30 for fixing the ladder to a window frame M of the building T and holding the ladder H to the window frame M. The locking member 30 for fixing the ladder includes two sets of substantially gate-shaped frames 31 connected by a connecting member 32, and includes an indoor side locking portion 33 and an outdoor side locking portion 34. The window frame M and the ladder H are sandwiched by the substantially gate-shaped frames 31, and a length adjusting mechanism 40 is provided to adjust the length of the locking member 30 for fixing the ladder in a direction corresponding to the dimension in the thickness direction N of the window frame M. It is characterized by the above. Hereinafter, it will be described based on the drawings. Note that the overall shape of the method for fixing a ladder and its locking member according to the present invention, and the shape of each dimension part are not limited to the description described below, and can be changed within the scope of the technical idea of the present invention, that is, within the scope of the shape and dimension that exhibit the same operational effect.

[0017] FIG. 1 is a basic process explanatory drawing for explaining the basic process of the method for fixing a ladder according to the present invention. FIG. 1(a) shows the overall configuration of the present invention, and FIG. 1(b) shows the working procedure in each process. Hereinafter, detailed explanations will be made for each component to be used.

[0018] The first ladder fixing method 1 is a method for fixing a ladder H to a building T, which consists of a first fixing means A and a second fixing means B. The first fixing means A includes an implanting step C of implanting a screwing member 10 into the walls K on both sides of the column F of the ladder H, and a tensioning step D1 of tensioning a rope or wire 11 through the step portion S of the ladder H by means of a ratchet type clamping machine 20 on the screwing member 10 implanted in the implanting step C. The second fixing means B is composed of a locking member holding step E of attaching a locking member 30 for fixing the ladder to the window frame M of the building T and holding the ladder H on the window frame M. The locking member 30 for fixing the ladder is provided with an indoor side locking portion 33 and an outdoor side locking portion 34, where two sets of substantially gate-shaped frames 31 are connected by a connecting member 32. The window frame M and the ladder H are clamped by the substantially gate-shaped frames 31, and a length adjusting mechanism 40 is provided to adjust the length of the locking member 30 for fixing the ladder in the direction corresponding to the dimension in the thickness direction N of the window frame M.

[0019] The first fixing means A is a means for fixing the ladder H to the wall K by means of a rope or wire 11 so that the upper part of the leaned ladder H cannot move to the left, right, and rear.

[0020] The second fixing means B is a means for fixing the ladder H to the window frame by using the locking member 30 so that the upper part of the leaned ladder H cannot move to the left, right, and rear.

[0021] The implanting step C is a step of implanting a screwing member such as an implanting bolt or an embedded nut after making a pilot hole for attaching the screwing member to the outer wall. The implanting position is preferably a position where strong building materials such as through columns, intermediate columns, and pipe columns pass through. And male threads protruding to the outside or female threads are formed on these screwing members, so a round ring or the like is screwed onto them. Note that due to the structural differences of the outer wall, the effectiveness of the anchor bolts varies greatly.

[0022] The tensioning step D1 is a step of tensioning the rope or wire 11 through the round ring or the like installed in the implanting step C by means of a ratchet type clamping machine 20 to a taut state.

[0023] The tensioning process D2 is a process in which ropes or wires 11 attached to the rings etc. installed in the planting process C are tensioned taut using ratchet-type load securing devices 20 positioned on the left and right sides of the ladder H.

[0024] The locking member holding step E is a step in which the ladder H and the window frame M are locked together by the locking member used in the second fixing means B, and the locking member is maintained in that state.

[0025] Figure 2 is an explanatory diagram of the configuration of the first fixing means, showing the configuration of the fixing device used in the first fixing means in the ladder fixing method according to the present invention.

[0026] Building T refers to any structure built for the purpose of people living in, storing goods, or working, generally having a roof and surrounding walls, and being fixed to the land, but it specifically refers to detached houses built using the wooden frame construction method.

[0027] A ladder H is a tool for climbing to high places, consisting of two long support posts F with several footholds S attached between them, and is used by leaning it against something.

[0028] The support column F is a component that forms a ladder H by being firmly connected to the ends of multiple step sections S. To securely lean a ladder against a roof, the top of the support post must extend at least 60 cm. If the protruding portion is less than 60 cm, the ladder may fall over with even a slight tremor. Extending the top of the ladder at least 60 cm is mandated by the Industrial Safety and Health Act and must be strictly adhered to.

[0029] The step section S refers to the treads, which should ideally have a width of 30 cm or more between the support posts, and be spaced at equal intervals of 25 cm to 35 cm.

[0030] The threaded member 10 refers to a metal fitting for forming a threaded portion in the wall K. For example, it is a member that forms a threaded portion corresponding to an eye bolt or the like using an anchor bolt (toggle bolt / board anchor) or a stud bolt with no head and male threads on both ends, to fix a hollow wall that is fixed by the tip of one end opening or spreading out like an umbrella and catching on it. Alternatively, it may be a member that has an embedded nut to form a female threaded portion into which an eye bolt or the like is screwed.

[0031] Rope or wire 11 refers to fiber ropes (fiber cords / fiber ropes) made by twisting natural or synthetic fibers together, and wire ropes (steel cords) made by using steel wire. Natural fiber ropes include Manila rope, cotton rope, sisal rope, hemp rope, palm rope, etc., while synthetic fiber ropes include a wide variety of types such as nylon rope, polyester rope, polyethylene rope, vinylon rope, Cremona rope, polypropylene rope, etc.

[0032] The ratchet-type cargo securing device 20 is used in the first securing means A of the ladder securing method 1 according to the present invention. By repeatedly turning the handle to wind up the belt, the length of the belt can be adjusted and it can be tightened securely. It is a tool for removing slack from a rope or wire wrapped around a support post and keeping it taut.

[0033] Figure 3 is an explanatory diagram of the configuration of the second fixing means, showing the configuration of the locking member used in the second fixing means in the ladder fixing method according to the present invention.

[0034] The ladder fixing locking member 30 is used in the second fixing means B in the ladder fixing method 1 according to the present invention, and is a member for fixing the ladder H by locking the ladder fixing locking member 30 to the window frame M. Specifically, a set of roughly gate-shaped frames 31 are fixed with connecting members 32 to form legs 35 at the four corners, and the indoor locking part 33, which is made up of two legs 35 located on the indoor side, and the outdoor locking part 34, which is made up of two legs 35 located on the outdoor side, contact and clamp the indoor wall K of the window frame M and the step part S of the ladder H, respectively, and the ladder H is clamped between the window frame M and the outdoor locking part 34, thus holding the window frame M and the ladder H. In the drawing, it is shown as being made of PVC pipe, but it is not limited to this, and the material may be a metal such as iron and the connecting part may be joined by welding.

[0035] The roughly gate-shaped frame 31 is a component that forms part of the ladder's fixing locking member 30, and is a roughly gate-shaped component formed by connecting one end of two roughly L-shaped legs 35 to a connecting rod, and the connecting rod 36 that connects the two legs 35 is equipped with a length adjustment mechanism 40 that can adjust the distance between the legs 35.

[0036] The connecting member 32 is a member used to connect a set of roughly gate-shaped frames 31. In the drawing, a flat plate is shown fixed by screws, but it may also be connected using pipe joints.

[0037] The indoor-side locking portion 33 is the part where the two legs 35 are joined by the connecting member 32, and this indoor-side locking portion 33 is the part that abuts against and holds the window frame M on the indoor side. In the drawing, one end is bent into an L shape, which is desirable in order to enlarge the contact surface and hold it firmly.

[0038] The outdoor locking portion 34 is a component for clamping the step portion S of the ladder H and the window frame M with the indoor locking portion 33.

[0039] Leg 35 is a leg section composed of a set of roughly gate-shaped frames.

[0040] The connecting rod 36 connects two legs 35 in a U-shape to form a roughly gate-shaped frame, and two of these are combined to form a locking member 30 for fixing the ladder. By adjusting the position of the joint with the legs 35, it also functions as a length adjustment mechanism 40 that can adjust the length to correspond to the width of the window frame M.

[0041] The length adjustment mechanism 40 consists of a connecting rod 36 that can adjust the length between the legs 35 of the roughly gate-shaped frame 31. In the drawing, the fixing position of the connecting rod 36 can be changed by a combination of pin holes and fixing pins, but it is also preferable to use a turn-lock type telescopic joint or a quick-lever type joint.

[0042] The clamping force assisting mechanism 50 fixes the positional relationship of the ladder H when it is locked to the window frame M, and holds it in place by pressing it against the fixing locking member 30 of the ladder that is locked to the window frame M.

[0043] Figure 4 is an explanatory perspective view showing the arrangement of the locking member used in the second fixing means of the ladder fixing method according to the present invention, when it is placed on a window frame.

[0044] A window frame M is a frame material installed in an opening in a building to fix the window glass and sash (joinery) and to neatly finish the surrounding area. It is a general term that includes the decorative part (frame) visible on the interior side and the base that supports the sash. Functionally, it plays a role in improving the insulation and airtightness of the room and also has a design aspect. It is a building material used to hold a ladder by coming into contact with the interior locking part 33 of the locking member used in the second fixing means in the ladder fixing method 1 according to the present invention.

[0045] The thickness direction N refers to the thickness direction of the lower frame portion of the window frame M from the inside to the outside. Since the thickness of this thickness direction N varies depending on the window frame M, its length can be adjusted by the length adjustment mechanism 40.

[0046] Figure 5 is an explanatory diagram showing the arrangement of the fastener used in the first fastening means and the locking member used in the second fastening means in the ladder fastening method according to the present invention, arranged on the window frame. Figure 5(a) is a front view showing the state in which the substantially gate-shaped frame of the locking member in the second fastening means is made substantially U-shaped to clamp the window frame M, and Figure 5(b) is a side view showing the same state.

[0047] In traditional wooden frame construction (conventional method), which consists of a framework of linear members such as columns, beams, and foundations, horizontal forces (earthquakes and wind pressure) are resisted by load-bearing walls such as bracing and structural plywood. However, wall K is generally installed to cover these load-bearing walls.

[0048] In the case of concrete and ALC panel walls, the wall itself is part of the structural frame, and due to its thickness and strength, anchors are very effective. By deeply embedding the screw members, high pull-out and shear strength can be achieved, making them suitable for fixing ladders. In contrast, in the case of mortar walls (lath base) made by applying mortar to layers of wood or metal lath (mesh), where there are cavities or underlying materials inside, the strength of the mortar layer itself is uneven, and direct fixing with anchors is not recommended. It is necessary to accurately identify the location of internal structural members such as columns and studs and use long screws or bolts that can reach them. Furthermore, in the case of ceramic and metal siding walls, which are "dry construction" finishing materials that are attached to underlying materials (such as furring strips) fastened to columns and studs, and where there is generally an air layer between the exterior wall material and the structural frame, the siding itself is thin, and anchors cannot provide sufficient holding power. Therefore, it is absolutely necessary to fix it to the internal structural frame (columns, studs, or concrete frame). In that case, bolts of the appropriate length, taking into account the thickness of the siding and the air gap, and special screw components will be required.

[0049] Figure 6 is an explanatory diagram of another arrangement showing the fastener used in the first fastening means and the locking member used in the second fastening means in the ladder fastening method according to the present invention, arranged on a window frame. Figure 6(a) is a front view showing the state in which the substantially gate-shaped frame of the locking member in the second fastening means is made crank-shaped to clamp the window frame M, and Figure 6(b) is a side view showing the same state.

[0050] Figure 6 shows a configuration in which, when the ladder's fixing locking member 30 is locked to the ladder's step portion S, the indoor locking portion 33 may not reach the window frame M. In this configuration, the indoor locking portion 33 is reversed and locked to the upper part of the indoor window frame M. By deforming the roughly gate-shaped frame into a crank shape in this way, it becomes possible to lock the ladder H regardless of the position of the step portion S relative to the window frame M.

[0051] Although not shown in the drawings, it is also preferable to place ladders H at the four corners of building T, apply the ladder fixing method according to the present invention to each, and use the protruding support columns F as lifeline support columns. By stretching horizontal lifelines to these lifeline support columns, falls during the assembly and dismantling of scaffolding at high altitudes are prevented, allowing workers to work safely and efficiently. Lifelines are products used to prevent falls and are used in connection with fall arrest equipment such as harnesses worn by workers. Lifelines are made of synthetic fibers (nylon) or reinforced with metal wire. Lifelines are divided into horizontal types used for horizontal movement and vertical types used for ascending and descending, and further divided into temporary and permanent types that can be removed. It is important to choose a lifeline that is appropriate for the work site and purpose. [Industrial applicability]

[0052] Since this invention ensures safety during work at heights using ladders, it can be adopted at construction sites and other locations. As it is a useful technology in the construction industry, its industrial applicability is considered to be high. [Explanation of Symbols]

[0053] T Building H ladder A. First fixing means B. Second fixing means C. Planting process D1 Tensioning process D2 Tensioning process E Locking member holding process F-post S Step section K wall M Window frame N thickness direction 1. How to secure a ladder 10 Threaded member 11. Rope or wire 20 Ratchet-type cargo securing devices 30 Ladder fixing locking member 31. Frame with a roughly gate-like shape 32 Connecting member 33 Indoor side locking part 34 Outdoor locking part 35 legs 36 connecting rods 40 Length adjustment mechanism 50 Clamping force assist mechanism

Claims

1. A method for fixing a ladder (H) to a building (T), The first fixing means (A), It consists of a second fixing means (B), The first fixing means (A) is, The planting process (C) involves planting screw-type members (10) into the walls (K) on both sides of the support posts (F) of the ladder (H), The process consists of a tensioning step (D1) in which a rope or wire (11) is stretched over the screw member (10) planted in the planting step (C) via the step portion (S) of the ladder (H) using a ratchet-type cargo securing device (20), The second fixing means (B) is, The process consists of a locking member holding step (E) in which a locking member (30) for fixing the ladder is attached to the window frame (M) of the building (T) to hold the ladder (H) to the window frame (M), The aforementioned ladder fixing locking member (30) comprises two sets of roughly gate-shaped frames (31) connected by a connecting member (32), and includes an indoor locking part (33) and an outdoor locking part (34). A method for fixing a ladder (1), characterized in that the window frame (M) and the ladder (H) are sandwiched by a frame (31) in a substantially gate shape, and a length adjustment mechanism (40) is provided that allows the length of a fixing locking member (30) for the ladder to be adjusted in the direction corresponding to the thickness direction (N) of the window frame (M).

2. In the first fixing means (A) described above, The planting process (C) involves planting screw-type members (10) into the walls (K) on both sides of the support posts (F) of the ladder (H), The ladder fixing method (1) according to claim 1, characterized in that it comprises a tensioning step (D2) in which a rope or wire (R) is tensioned on the screw member (10) planted in the planting step (C) using ratchet-type load securing devices (20) positioned on the left and right sides via the step portion (S) of the ladder (H).

3. A ladder fixing locking member (30) for fixing a ladder (H) used in a second fixing means (B) of a ladder fixing method (1) according to claim 1 or claim 2, The fixing locking member (30) of the ladder consists of two sets of roughly gate-shaped frames (31) connected by a connecting member (32) to form an indoor locking portion (33) and an outdoor locking portion (34). A ladder fixing locking member (30) is characterized by clamping the window frame (M) and the ladder (H) between the indoor locking portion (33) and the outdoor locking portion (34), and being equipped with a length adjustment mechanism (40) that allows the length of the locking member (30) to be adjusted in the direction corresponding to the thickness direction (N) of the window frame (M).

4. The ladder fixing locking member (30) according to claim 3, characterized in that the ladder fixing locking member (30) is provided with a clamping force assisting mechanism (50) for increasing the clamping force when the ladder (H) is clamped by the substantially gate-shaped frame (31).

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