Fire ladder

Abstract

The utility model relates to the field of fire-fighting equipment, in particular, it relates to the category of fire-fighting ladders - specialized vehicles for rapid response. The boom of the fire-fighting ladder is made in the form of a set of telescopic U-shaped knees, including a fixed knee 2 and movable telescopic knees 1. Each knee is formed by two side trusses 3, each of which consists of an upper 5 and a lower chord 6, connected to each other by struts 4, and the trusses themselves are connected to each other by steps 7. The main load is supported by the lower chords of the side trusses 6, which are made of a bent closed section 8 from a metal strip, consisting of one hexagonal upper profile 8.1 and one nine-sided lower profile 8.2. Each hexagonal upper profile has three horizontal, two vertical and one inclined faces, each nine-sided profile has four horizontal and five vertical faces.The utility model allows for improved manufacturability of the fire ladder design while maintaining its load-bearing capacity.

Description

[0001] This utility model pertains to fire-fighting equipment, specifically fire ladder trucks—specialized rapid response vehicles. These vehicles are built on a truck chassis and equipped with fire-fighting equipment and tools used in emergency rescue operations.

[0002] Technical requirements for this equipment are regulated by GOST R 34729-2021 "Firefighting equipment. Fire ladders. General technical requirements. Test methods."

[0003] Fire ladders are equipped with a special telescopic boom mechanism. The boom is constructed from a system of movable sections (knees) that form a continuous flight of stairs.

[0004] The main purpose of aerial ladders is to carry out emergency rescue operations, evacuate people from heights, and extinguish fires in multi-story buildings.

[0005] In the Russian Federation and abroad, fire-fighting ladders with a lifting height of up to 80 meters with a boom consisting of knees, usually up to 12 meters long, are mass-produced.

[0006] The closest analogue of the presented utility model is the "Fire Elevator Ladder" design described in invention patent RU 2056502 C1, with a priority date of March 24, 1992. This design includes a boom device consisting of telescopically folding sections, designed as two parallel truss structures with upper and lower chords. The lower chords are formed by a set of box-shaped metal profiles with horizontal and vertical walls, connected during installation to create V- and Z-shapes, forming at least three closed cavities. The outer surface of these cavities serves as a support for the rolling of the guide rollers of adjacent boom sections. The profiles are shaped like the letters L and T, with their vertical shelves forming an additional third cavity when mated with the horizontal walls of the profiles. One of the walls of the upper L-shaped profile is bent inward at an acute angle.

[0007] The disadvantages of the prototype under consideration are as follows:

[0008] 1. The design of the lower chords of the side trusses utilizes T- and L-shaped sections with a rectangular cross-section at the bottom, which have low rigidity. This necessitates an increase in the cross-sectional area to achieve the required strength, leading to increased metal consumption.

[0009] 2. Manufacturing a set of elbows requires the use of three types of profiles with different cross-sectional shapes, which complicates production. Since the production of long, thin-walled, high-precision profiles is only possible using specialized, expensive CNC sheet bending machines with laser welding, the variety of profile types used increases the cost and complexity of manufacturing the stair elbows due to the increased volume of necessary technological equipment and the need for frequent equipment readjustment when changing profile types.

[0010] Considering the above problems, there is a need to optimize the design and standardize the profiles for the lower chords of the side trusses of the U-shaped elbows in order to increase strength, reduce metal consumption and improve the manufacturing efficiency of telescopic elbows of fire truck ladders in general.

[0011] The technical objective of the utility model is to increase the strength of a fire ladder by reducing the metal content of the lower chords of the side trusses of the knees of fire ladders while simultaneously increasing the manufacturability of their design.

[0012] The technical result of the proposed utility model is to improve the manufacturability of the fire ladder design while maintaining the load-bearing capacity.

[0013] The technical result is achieved in that the fire ladder contains a boom made from a set of telescopic U-shaped knees, each of which consists of two side trusses, the lower chords of which are formed by box-section profiles, according to the proposal, the telescopic U-shaped knees include one fixed knee and five movable telescopic knees,

[0014] The lower belts are made in the form of a closed profile from a metal strip, consisting of one hexagonal upper profile and one nine-sided lower profile,

[0015] Each hexagonal top profile has three horizontal, two vertical and one inclined faces, each nine-sided profile has four horizontal and five vertical faces,

[0016] wherein the lower horizontal closing edge of each profile is welded to the vertical closing edge in the middle of its length,

[0017] A hexagonal upper profile and a nine-sided lower profile are connected to each other by welding the vertical closing faces with the horizontal closing faces at the points of their bending, forming a common fifteen-sided closed profile with three internal stiffeners.

[0018] One of the possible options for implementing the design of a fire ladder assumes that each hexagonal upper profile consists of a lower horizontal closing face, a left vertical face, an upper horizontal face, an inclined face, a right horizontal face and a vertical closing face.

[0019] The bending radius of each face of the hexagonal upper profile and the nine-sided lower profile is no more than two thicknesses of the metal strip.

[0020] The internal angle between the upper horizontal face and the inclined face of the hexagonal top profile is 135°, and the vertical closing face of the hexagonal top profile ends with a bend at an angle of 150° and a length equal to two thicknesses of the metal strip.

[0021] The technical characteristics of the proposed utility model can be implemented using standard methods and technologies widely used in the mechanical engineering industry.

[0022] Brief description of drawings.

[0023] Fig. 1 shows a general view of the set of telescopic elbows of a fire truck ladder.

[0024] Fig. 2 shows a diagram of the cross-section of the lower chord of the side trusses of the knee, assembled from two standard heptagonal profiles.

[0025] Fig. 3 shows a cross-sectional diagram of the entire set of telescopic elbows.

[0026] Fig. 4 shows a diagram of the load distribution on the edge of the lower chord of the side trusses.

[0027] The following positions are indicated in Fig. 1 - Fig. 4:

[0028] 1 - movable knee;

[0029] 2 - fixed knee;

[0030] 3 - side trusses;

[0031] 4 - spacers;

[0032] 5 - upper belt;

[0033] 6 - lower belt;

[0034] 7 - steps;

[0035] 8 - bent closed profile;

[0036] 8.1 - hexagonal top profile;

[0037] 8.2 - nine-sided bottom profile;

[0038] 9 - upper horizontal edge;

[0039] 10 - inclined edge;

[0040] 11 - left vertical edge;

[0041] 12 - right horizontal edge;

[0042] 13- vertical closing edge;

[0043] 14 - bend at an angle of 150°;

[0044] 15 - left vertical edge;

[0045] 16 - lower horizontal closing edge;

[0046] 17 - weld;

[0047] 18 - weld;

[0048] 19 - telescopic knees;

[0049] 20 - fixed knee;

[0050] 21 - one guide roller block;

[0051] 21.1 - roller support;

[0052] 22 - two blocks of side guide rollers;

[0053] 22.1 - roller support;

[0054] 23 - guide roller;

[0055] 24 - loads on the edge of the lower belt of the telescopic knee.

[0056] Implementation of a utility model.

[0057] A boom of a fire ladder, made in the form of a set of telescopic U-shaped elbows (Fig. 1), including a fixed elbow 2 and movable telescopic elbows 1 (one elbow is shown conditionally in the drawing).

[0058] Each knee is formed by two side trusses 3, each of which consists of an upper 5 and lower chord 6, connected to each other by spacers 4, and the trusses themselves are connected to each other by steps 7. The main load is supported by the lower chords of the side trusses 6 (Fig. 2), which are made of a bent closed profile 8 from a metal strip, consisting of one hexagonal upper profile 8.1 and one nine-sided lower profile 8.2. Each hexagonal upper profile has three horizontal, two vertical and one inclined faces, each nine-sided profile has four horizontal and five vertical faces.

[0059] Each of the 8 profiles includes the following elements:

[0060] - upper horizontal edge 9;

[0061] - inclined edge 10;

[0062] - left vertical edge 11;

[0063] - right horizontal edge 12;

[0064] - vertical closing edge 13, at the end of which there is a bend 14 at an angle of 150° and a length equal to twice the thickness of the metal;

[0065] - left vertical edge 15;

[0066] - lower horizontal closing edge 16.

[0067] Each hexagonal top profile 8.1 consists of a lower horizontal closing face 16, a left vertical face 15, an upper horizontal face 9, an inclined face 10, a right horizontal face 12 and a vertical closing face 13.

[0068] The lower horizontal closing face 16 is joined by a weld 17 to the middle of the vertical closing face 13.

[0069] Thus, the hexagonal upper profile and the nine-sided lower profile are connected to each other by welding the vertical closing faces 13 with the horizontal closing faces at the points of their bending, forming a common fifteen-sided closed profile with three internal stiffening ribs.

[0070] The radius of curvature of each edge of profile 8 is no more than twice the thickness of the metal strip used, ensuring precise geometry and straightness along the entire length of the profile, which positively impacts the strength characteristics of the structure. Inclined edge 10 is positioned at an angle of 135° to the upper horizontal edge 9, which contributes to increased rigidity of these edges.

[0071] The closed profile 8 consists of a hexagonal upper profile 8.1 and a nine-sided lower profile 8.2 (Fig. 2, Fig. 4), connected by welded seams 18 by attaching vertical closing faces 13 to horizontal closing faces 16 at their inflection points, forming a single fifteen-sided product with three internal stiffening ribs.

[0072] The task of forming an upper closing edge with a bent end, the length of which is equal to twice the thickness of the metal strip and is located at an angle of 150° to the vertical closing edge 13, facilitates the connection and welding of the upper closing edges with the horizontal closing edges, which additionally guarantees precise adherence to the profile geometry and its straightness along the entire length.

[0073] Fig. 3 shows a cross-section of a set of telescopic knees, including a fixed knee 20 and telescopic knees 19 (the illustration shows the conventional left side from the axis of the ladder).

[0074] The main forces of load perception and transmission are carried out by the lower belts 6 of the side trusses 3, which also serve as the basis for installing support and guide rollers, with some edges of the profile serving as rolling planes for these rollers.

[0075] The following equipment is placed on each lower chord of the telescopic elbow, represented by the lower profile 8.2:

[0076] - two blocks of side guide rollers 22 with a vertical axis of rotation, installed in the upper and lower parts of the lower belts of the knees;

[0077] - one support roller block 21 with a horizontal axis of rotation, located at the bottom of the lower belts of the knees;

[0078] - one guide roller block 23 with a horizontal rotation axis, installed in the upper part of the lower belt of the knees.

[0079] Fig. 3 shows rollers only on two telescopic knees (outer and inner) for clarity.

[0080] The ladder extension process is realized by means of the specified set of rollers and the telescopic knee extension device (not shown in the diagram).

[0081] When the telescopic legs are fully extended, the ladder is subject to a complex combination of forces:

[0082] - the force from the boom's own weight together with the installed equipment (cradle with cargo, elevator for rescuing people, fire extinguishing agent supply system, etc.), creating the greatest bending moment;

[0083] - lateral influences (e.g. wind, boom deviation from the vertical);

[0084] - lateral bending moment when one branch of the extension traction mechanism is weakened.

[0085] The loads acting on the ladder legs are transmitted through the lower chords of the legs thanks to the specified support and guide rollers. Fig. 4 shows the distribution of loads 24 on the edge of the lower chord of the telescopic leg.

[0086] The installation of the side guide rollers 22, the support roller 21 and the guide roller 23 is carried out on the outer knee, while similar blocks 21.1 and 23 are located on the lower belt of the inner knee.

[0087] Thus, the main load zones become the three edges of the lower profile 8.2 (see Fig. 2) and two edges of the upper profile 8.1.

[0088] Using the smallest possible bending radius, equal to no more than two thicknesses of the metal strip, in the design of profiles allows for maximum straightness of the profile along its entire length and minimizes deformations that negatively affect the strength of the structure.

[0089] Forming inclined edges in profiles increases the rigidity of the profile section, enhancing its strength while simultaneously reducing material consumption, which collectively achieves the desired technical effect of the claimed utility model. The use of one hexagonal and one nine-sided unified profile halves the number of required section shapes for the stair elbows compared to previous designs, significantly simplifying their production.

[0090] Welding the lower horizontal closing face to the vertical closing face in the middle creates three additional points of rigidity for the fifteen-sided profile, ensuring optimal reception of lateral forces acting on the vertical closing face from the side guide rollers.

[0091] The proposed technical solutions were developed based on many years of experience in the design, production and testing of domestic fire ladders, as well as the study of foreign analogues.

Claims

1. A fire ladder comprising a boom made from a set of telescopic U-shaped elbows, each of which consists of two side trusses, the lower chords of which are formed by box-section profiles, characterized in that the telescopic U-shaped elbows include one fixed elbow and five movable telescopic elbows, the lower belts are made in the form of a closed profile from a metal strip, consisting of one hexagonal upper profile and one nine-sided lower profile, each hexagonal top profile has three horizontal, two vertical and one inclined faces, each nine-sided profile has four horizontal and five vertical faces, wherein the lower horizontal closing edge of each profile is welded to the vertical closing edge in the middle of its length, and the hexagonal upper profile and the nine-sided lower profile are connected to each other by welding the vertical closing faces with the horizontal closing faces at the points of their bending, forming a common fifteen-sided closed profile with three internal stiffening ribs.

2. A fire ladder according to paragraph 1, characterized in that each hexagonal upper profile consists of a lower horizontal closing edge, a left vertical edge, an upper horizontal edge, an inclined edge, a right horizontal edge, and a vertical closing edge.

3. A fire ladder according to paragraph 1, characterized in that the bending radius of each face of the hexagonal upper profile and the nine-sided lower profile is equal to no more than two thicknesses of the metal strip.

4. A fire ladder according to paragraph 2, characterized in that the internal angle between the upper horizontal edge and the inclined edge of the hexagonal upper profile is 135°, and the vertical closing edge of the hexagonal upper profile ends with a bend at an angle of 150° and a length equal to two thicknesses of the metal strip.

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