An external formwork system for concrete structures

Abstract

The utility model provides a kind of for concrete structure's outer mould system, construction support field, comprising: horizontal stress component, first end is provided with first bind seat, second end is provided with second bind seat, first bind seat and second bind seat are used to be fixed to ground;First telescopic unit, hinged in the second end of horizontal stress component;Second telescopic unit, hinged in the middle portion of horizontal stress component, formwork unit, hinged in the other end of first telescopic unit and second telescopic unit, the reinforcing mode of the present application changes inner pull welding draw bar, the mode of external support is supported to formwork body, so that formwork has the ability of anti-lateral impact, avoid when incorporating sheet stone between formwork body to cause damage to draw bar.

Description

Technical Field

[0001] This utility model relates to the field of construction support, and in particular to an external formwork system for concrete structures. Background Technology

[0002] In the construction of bridge abutments, culvert abutments, roadbed retaining walls, and other rubble concrete structures, external formwork is required, and the formwork must be reinforced before concrete pouring. Current engineering projects commonly use internally welded tie rods for formwork reinforcement, forming a crisscrossing grid-like reinforcement system. However, when a certain amount of rubble needs to be added according to specifications during concrete pouring, existing reinforcement methods have significant technical defects: the actual amount of rubble added is often lower than the specification requirements, leading to material waste and increased project costs; simultaneously, collisions between rubble and tie rods during manual material addition can easily cause formwork deformation accidents. To address these problems, this application proposes an innovative external formwork system for concrete structures. Utility Model Content

[0003] This utility model provides an external formwork system for concrete structures, the purpose of which is to solve the problem that existing external formwork requires internal tie rods to pour rubble concrete.

[0004] To achieve the above objectives, embodiments of this utility model provide an external formwork system for concrete structures, comprising:

[0005] A horizontal force-bearing component has a first hinge at one end and a second hinge at the second end, the first hinge and the second hinge being used to fix it to the ground;

[0006] The first telescopic unit is hinged to the second end of the horizontal force-bearing component;

[0007] The second telescopic unit is hinged to the middle of the horizontal force-bearing component.

[0008] The template unit is hinged to the other end of the first telescopic unit and the second telescopic unit.

[0009] Preferably, the external formwork system for the concrete structure further includes a third telescopic unit, one end of which is hinged to the horizontal force-bearing component, and the other end is provided with a third hinge seat. The third hinge seat and the first hinge seat are used to fix the existing concrete structure to the side.

[0010] Preferably, the template unit includes several template components, which can be assembled in the length direction and / or height direction;

[0011] The external formwork system for concrete structures also includes a back beam unit, which is detachably connected to the formwork unit, and the first telescopic unit and the second telescopic unit are hinged to the back beam unit.

[0012] Preferably, the back beam unit is used to adjust multiple template units onto the same vertical plane;

[0013] The template assembly includes a template body and template crossbeams and template longitudinal beams disposed on the template body. The template crossbeams and template longitudinal beams are fixed to the template body in a grid pattern.

[0014] The back beam unit includes at least two sets of back beams, each set of back beams includes two beams, and the two back beams in each set are spaced apart above and below the same template beam; a first connecting block can also be detachably connected to the back beams in each set, the first connecting block is used to limit the distance between the two back beams in each set in the height direction.

[0015] The first telescopic unit and the second telescopic unit are hinged to a second connecting block at one end near the template unit, and the second connecting block is detachably connected to the first connecting block.

[0016] The external formwork system for concrete structures also includes a clamping unit for clamping the formwork unit against the back beam.

[0017] Preferably, the clamping unit includes a center plate and two clamping plates spaced apart along the height direction. The first ends of the two clamping plates are detachably connected to the template beam. The center plate is inserted between the two clamping plates by the second ends of the two clamping plates and is fixedly connected to the two clamping plates. The center plate is provided with a wedge hole, and a wedge plate is inserted into the wedge hole. The wedge plate moves downward in the wedge hole to pull the template unit against the template beam.

[0018] Preferably, the template assembly is connected along its length by connecting bolts.

[0019] Preferably, the back beam is a channel steel.

[0020] Preferably, the first telescopic unit, the second telescopic unit, and the third telescopic unit each include a screw and a connecting part, the two ends of the screw have reverse threads, and the two connecting parts are respectively screwed onto the screw.

[0021] Preferably, a second pull rope is connected between the first telescopic unit and the horizontal force-bearing component, and a third pull rope is connected between the second telescopic unit and the horizontal force-bearing component.

[0022] Preferably, the horizontal force-bearing component is a horizontal frame, and several groups of the first telescopic unit and the second telescopic unit are arranged along the length direction of the horizontal force-bearing component, and several groups of the first telescopic unit and the second telescopic unit are installed on the same back beam unit.

[0023] The above-mentioned solution of this utility model has the following beneficial effects:

[0024] First, this application changes the reinforcement method of the internally welded tie rods and adopts external support to support the template body, so that the template has the ability to resist lateral impact and avoids damage to the tie rods when adding rubble between the template bodies.

[0025] Secondly, this application can be used not only for pouring operations on horizontal ground, but also for pouring layer by layer in the vertical direction, making it more widely applicable.

[0026] Third, this application adds a clamping unit between the back beam unit and the formwork unit to relieve the gravity pressure between the back beam and the formwork plate, reduce the deflection and bending of the back beam and the formwork plate. At the same time, the clamping unit can also form stress dispersion, reduce the load on the bolts, and transform the local concentrated load into a uniformly distributed load, which helps to maintain the stability of the formwork unit.

[0027] Fourth, this application adopts a modular combination, which facilitates transportation and disassembly, and can reduce the space occupied during transportation and storage.

[0028] Other features and advantages of this invention will be described in detail in the following detailed description section. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the first type of external mold system;

[0030] Figure 2 This is a schematic diagram of the first type of external mold system.

[0031] Figure 3 This is a schematic diagram of the second type of external mold system;

[0032] Figure 4 This is a schematic diagram of the second type of external mold system;

[0033] Figure 5 yes Figure 2 A diagram of AA in the middle;

[0034] Figure 6 It is a three-dimensional schematic diagram of the back beam unit, template unit and clamping unit;

[0035] Figure 7 yes Figure 6 Enlarged view of section B;

[0036] Figure 8 This is the formula Figure 6 Rear view;

[0037] Figure 9 This is a cross-sectional view of the clamping unit;

[0038] Figure 10 This is a schematic diagram of the limiting component.

[0039] [Explanation of Labels in the Attached Image]

[0040] 100 - Horizontal load-bearing component, 110 - First winch seat, 120 - Second winch seat

[0041] 200 - First telescopic unit, 210 - Second connecting block, 220 - Screw, 230 - Connecting part

[0042] 300 - Second telescopic unit

[0043] 400-Formwork unit, 410-Formwork assembly, 411-Formwork body, 412-Formwork crossbeam, 413-Formwork longitudinal beam,

[0044] 500 - Third telescopic unit, 510 - Third hinged seat

[0045] 600 - Back beam unit, 610 - Back beam crossbeam, 620 - First connecting block, 621 - First connecting hole, 630 - First pull rope, 640 - Second pull rope, 650 - Corner structure, 670 - Third pull rope

[0046] 700-Clamping unit, 710-Center plate, 720-Clamping plate, 721-Second bolt, 740-Wedge plate, 750-Limiting component,

[0047] A1 - First embedded part, A2 - Second embedded part

[0048] B1 - First outer mold system, B2 - Second outer mold system, B3 - Third outer mold system, B4 - Fourth outer mold system. Detailed Implementation

[0049] To make the technical problems, technical solutions and advantages of this utility model clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0050] In this application, the plane containing the length and height is a longitudinal plane, and the plane containing the width and length is a horizontal plane or a transverse plane.

[0051] like Figures 1-10 As shown, an embodiment of this utility model provides an external formwork system for concrete structures, such as... Figure 1The device includes a horizontal force-bearing component 100, a first telescopic unit 200, a second telescopic unit 300, and a template unit 400. The horizontal force-bearing component 100 has a first hinge 110 at one end and a second hinge 120 at the other end. The first hinge 110 and the second hinge 120 are used to fix the device to the ground or the side of an existing concrete structure. One end of the first telescopic unit 200 is hinged to the second end of the horizontal force-bearing component 100, and one end of the second telescopic unit 300 is hinged to the middle of the horizontal force-bearing component 100. The template unit 400 is hinged to the other end of the first telescopic unit 200 and the second telescopic unit 300. From a longitudinal perspective, the first telescopic unit 200, the second telescopic unit 300, and the template unit 400 form a triangular structure.

[0052] Specifically, the template unit 400 is located on one side near the first end of the horizontal load-bearing component 100. The first hinge 110 and the second hinge 120 are fixed by a first embedded part A1 pre-embedded in the ground or existing concrete structure. The first embedded part A1 can be a pre-embedded bolt, etc. The pre-embedded bolt is detachably connected to the first hinge 110 and the second hinge 120, thereby fixing the first hinge 110 and the second hinge 120 to the ground or existing concrete structure, thereby supporting the horizontal load-bearing component 100.

[0053] The two telescopic units can adjust the angle between the template unit 400 and the ground by adjusting their own length, thereby adjusting the angle of the template unit 400 so that the poured concrete has an angle that meets the process specifications.

[0054] Preferably, a second embedded part A2 is detachably provided on the template unit 400. The second embedded part A2 can also be a pre-embedded bolt. Two second embedded parts A2 are provided along the longitudinal direction.

[0055] This embodiment is used for cases where casting and molding are performed on the ground. For example... Figure 2When using the structure of this embodiment, firstly, pre-embedded bolts are driven into the vicinity of the location where concrete needs to be poured, or pre-embedded bolts are left in advance when constructing the area. Multiple external formwork systems for the concrete structure are then fixed to the ground sequentially. At this time, the horizontal force-bearing component 100 is fixed to the ground via the first hinge 110 and the second hinge 120. Multiple formwork units 400 of the external formwork systems for the concrete structure surround to form a rectangular space, which is used for pouring concrete. The bottom end of the formwork unit 400 is supported on the ground, and the angle between the formwork unit 400 and the ground is adjusted by adjusting the first telescopic unit 200 and the second telescopic unit 300. Generally, the angle between the formwork unit 400 and the ground is a right angle. In some special cases, when the concrete structure to be poured has an inclined surface (such as a dam), the angle between the formwork unit 400 and the ground is adjusted according to the construction process. It should be emphasized that when the angle between the formwork unit 400 and the ground is not a right angle, mortar needs to be filled into the triangular gap formed between the formwork unit 400 and the ground to seal the bottom.

[0056] After multiple template units 400 of this embodiment form a rectangular space, concrete and rubble are poured into the rectangular space from above. The pouring method is described in the prior art. Since there are no tie rods inside the rectangle, the problem of rubble impacting and damaging the tie rods, as mentioned in the prior art, will not occur. At the same time, the horizontal force-bearing component 100, the first telescopic unit 200, and the second telescopic unit 300 support the template outside the rectangular space. After the concrete has cured, the system can be dismantled.

[0057] When dismantling this system, if it is necessary to pour concrete upwards again, the second embedded part A2 needs to be left in the poured concrete.

[0058] This application also provides another embodiment, such as Figure 3 As shown, in addition to the aforementioned components, the external formwork system for the concrete structure also includes a third telescopic unit 500. One end of the third telescopic unit 500 is hinged to the horizontal force-bearing component 100, and the other end is provided with a hinged third hinge seat 510. The third hinge seat 510 is used to fix it to the side of the existing concrete structure, and the first hinge seat 110 is fixedly connected to the second embedded part A2 reserved in the existing concrete.

[0059] The external formwork system for concrete structures provided in this embodiment is applied to layer-by-layer upward pouring.

[0060] like Figure 4As shown, after the lower concrete structure solidifies to form the existing concrete structure, the third hinge 510 is fixed to the second embedded part A2 below the existing concrete structure, and the first hinge 110 is fixed to the second embedded part A2 above the existing concrete structure. The length of the third telescopic unit 500 is adjusted so that the horizontal force-bearing component 100 located above the third telescopic unit 500 is in a horizontal state. In this embodiment, the third telescopic unit 500 provides support for the horizontal force-bearing component 100, and the side of the existing concrete structure, the third telescopic unit 500, and the horizontal force-bearing component 100 form a triangular support structure, which can maintain the horizontal force-bearing component 100.

[0061] The template unit 400 is supported on the first hinge 110, which facilitates the support of the template unit 400 and the adjustment of the angle between the template and the ground.

[0062] Understandably, if it is necessary to continue pouring upwards, the second embedded part A2 needs to be detachably installed on the formwork unit 400.

[0063] The external formwork system for concrete structures provided in this embodiment can be poured layer by layer in the longitudinal direction, and its application range is wider than that of existing external systems.

[0064] Combination Figure 5-9 As shown, in the two embodiments described above, the template unit 400 includes a plurality of template components 410. The multiple template components 410 can be assembled in the length direction or the height direction, so that the template unit 400 can form template units 400 of different specifications with the template components 410 as the smallest unit. The template component 410 includes a template body 411. A template crossbeam 412 and a template longitudinal beam 413 are provided on one side of the template body 411. The template crossbeam 412 and the template longitudinal beam 413 are fixed on the template body 411 in a grid pattern. It can be understood that at least two template crossbeams 412 and template longitudinal beams 413 are provided respectively. When the template crossbeams 412 and template longitudinal beams 413 are provided at the edge of the template body 411, they can be understood as the edge beams of the template body 411.

[0065] This application also includes a backing unit 600, which serves as a reference surface for the plurality of template components 410 and fixes and supports the template components 410.

[0066] Specifically, the back beam unit 600 includes at least two sets of back beam crossbeams 610. The two sets of back beam crossbeams 610 are spaced apart along the height direction of the template unit 400 on the template assembly 410. Each set of back beam crossbeams 610 includes two beams. The back beam crossbeams 610 in each set are spaced apart above and below the crossbeams of the same template in the height direction. A first connecting block 620 is detachably provided on each set of back beam crossbeams 610. The first connecting block 620 is used to fix and limit the distance between the back beam crossbeams 610 in the height direction within each set. Several first connecting blocks 620 are provided along the length direction of the back beam crossbeams 610. A second connecting block 210 is hinged to one end of the first telescopic unit 200 and the second telescopic unit 300 near the template unit 400. The second connecting block 210 is detachably connected to the first connecting block 620.

[0067] This application also includes a clamping unit 700 for clamping the template assembly 410 against the back beam 610.

[0068] Specifically, at least two sets of back beams 610 are provided along the height direction of the template unit 400. Multiple sets of back beams 610 are arranged according to the height of the template assembly 410 and the stress. It is understandable that the higher the height of the template unit 400, the higher the number of sets of back beams 610 required.

[0069] As mentioned above, the template assembly 410 includes at least two template beams 412, with the aforementioned back beam 610 disposed at two of the template beams 412. The length of the back beam 610 is the same as the total length of the template unit 400, allowing multiple template assemblies 410 to be installed with the back beam 610 as a reference. A second connecting block 210 is connected to one end of the first telescopic unit 200 and the second telescopic unit 300 near the template unit 400. The second connecting block 210 is connected to the first telescopic unit 200 or the second telescopic unit 300 via a hinge seat. The first connecting block 620 and the second connecting block 210 are provided with corresponding first connecting holes 621 for inserting first bolts, thereby connecting the first connecting block 620 and the second connecting block 210.

[0070] The clamping unit 700 includes a center plate 710 and two clamping plates 720 spaced apart along the height direction. The first ends of the two clamping plates 720 are detachably connected to the template beam 412. The template beam 412 is provided with second connecting holes, and the first ends of the two clamping plates 720 are also provided with second connecting holes. The two second connecting holes are used to pass through second bolts 721, thereby realizing the detachable connection between the clamping plates 720 and the template beam 412. The aforementioned center plate 710 is inserted between the two clamping plates 720 by the second ends of the two clamping plates 720, and the center plate 710 is fixedly connected to the two clamping plates 720 respectively, preferably by welding. A wedge hole is also provided on the center plate 710. The wedge hole is an oblong hole, which is opened along the line connecting the first end and the second end of the center plate. The other end of the center plate 710 protrudes through the gap between the back beam beams 610, and the wedge hole is located on the part of the center plate 710 that protrudes from the back beam beam 610. A wedge plate 740 is also inserted into the wedge hole. The wedge is a right triangle. When the wedge plate 740 is inserted into the wedge hole, the wedge plate 740 uses the side of the back beam 610 near the wedge plate 740 as the force surface, which pushes the center plate 710 to move, thereby pulling the back beam unit 600 to press against the other side of the back beam 610.

[0071] Preferably, a limiting member 750 is further provided above the center plate 710. The limiting member 750 is located above the wedge hole, is U-shaped, and is detachably mounted on the center plate, abutting against the wedge plate 740 to prevent the wedge plate from loosening upwards. Preferably, the height of the limiting member 750 can be adjusted by adding shims between the limiting member 750 and the center plate 710, ensuring that the limiting member 750 can abut against the wedge plate 740 and connect with the center plate 710.

[0072] In this embodiment, the back beam 610 is made of channel steel, and the two flanges of the channel steel can form surface contact with the template assembly 410 or the wedge plate 740, reducing the probability of deformation.

[0073] The aforementioned back beam 610 is also provided with a first connecting hole 621, and the first connecting block 620, the second connecting block 210 and the first connecting hole 621 on the back beam 610 are connected together by a first bolt.

[0074] A second connecting hole is also provided on the aforementioned back beam. When multiple template components 410 need to be connected in the length direction, the template beams 413 near the edge of two template components 410 can be connected using connecting bolts.

[0075] In this application, by setting the clamping unit 700, the load on the clamping plate 720 is reduced. At the same time, by using the flange of the back beam 610 to abut against the template longitudinal beam 413 and the wedge plate 740, the locally concentrated load is converted into a uniformly distributed load, which reduces the probability of damage to the back beam 610, the template longitudinal beam 413 and the wedge plate 740, and also improves the stability of the template unit 400.

[0076] In this application, the edge of the back beam 610 may also have a detachable bend structure 650, which is used to detachably set the first pull rope 630 or connect other back beams 610.

[0077] Specifically, the bending angle of the corner structure 650 is 90 degrees. One end of the corner structure 650 is connected to the edge of the back beam 610 by bolts, and the other end is connected to another back beam 610. The angle between the two back beams 610 in the top view is a right angle.

[0078] Reference Figure 5 As shown, when the outer mold system forms a rectangular space, each side can be connected in a straight line by several template units 400 and back beam units 600 in a one-to-one correspondence. In this figure, there are a first outer mold system B1, a second outer mold system B2, a third outer mold system B3 and a fourth outer mold system B4. The first outer mold system B1, the second outer mold system B2 and the third outer mold system B3 are connected end to end in sequence. The first outer mold system B1 and the third outer mold system B3 are perpendicular to the second outer mold system B2. The fourth outer mold system B4 is parallel to the second outer mold system B2. The two ends of the fourth outer mold system B4 are detachably connected to the side of the first outer mold system B1 and the third outer mold system B3 away from the second outer mold system B2 by bolts, but are not located at the ends of the first outer mold system B1 and the third outer mold system B3. The aforementioned bend structure 650 is installed on the back beam 610 of the first outer mold system B1 and the third outer mold system B3 near the fourth outer mold system B4. A first pull rope 630 is detachably installed on the bend structure 650, connecting the back beam 610 of the fourth outer mold system B4 to the back beams 610 of the third outer mold system B3 and the first outer mold system B1. The first pull rope 630 further enhances the connection strength between the first outer mold system B1, the third outer mold system B3, and the fourth outer mold system B4.

[0079] In one embodiment of this application, the first telescopic unit 200, the second telescopic unit 300, and the third telescopic unit 500 have the same structure. Taking the first telescopic unit 200 as an example, it includes a screw 220 and connecting portions 230 screwed to both ends of the screw 220. The connecting portions 230 are used to hinge the horizontal force-bearing component 100 or the back panel of the back panel unit 600. The two ends of the screw 220 have reverse threads, so that when the screw 220 is rotated, the two connecting portions 230 can move closer or further apart synchronously.

[0080] In one embodiment of this application, a second pull rope 640 is further connected between the first telescopic unit 200 and the horizontal force-bearing component 100, and a third pull rope 670 is connected between the second telescopic unit 300 and the horizontal force-bearing component 100.

[0081] In this application, the horizontal force-bearing component 100 is a horizontal frame. Preferably, the horizontal force-bearing component 100 is a grid-shaped frame. A plurality of first telescopic units 200 and second telescopic units 300 are arranged along the width direction of the horizontal force-bearing component 100. The first telescopic units 200 and second telescopic units 300 located on the same horizontal hydraulic component are fixed on the same back panel.

[0082] Understandably, several third telescopic units 500 are also provided along the length of the horizontal force-bearing component 100.

[0083] The above description is the preferred embodiment of this utility model. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of this utility model, and these improvements and modifications should also be considered within the protection scope of this utility model.

Claims

1. An external formwork system for concrete structures, characterized in that, include: A horizontal force-bearing component (100) has a first hinge (110) at one end and a second hinge (120) at the second end. The first hinge (110) and the second hinge (120) are used to fix the component to the ground. The first telescopic unit (200) is hinged to the second end of the horizontal force-bearing component (100); The second telescopic unit (300) is hinged to the middle of the horizontal force-bearing component (100). The template unit (400) is hinged to the other end of the first telescopic unit (200) and the second telescopic unit (300).

2. The external formwork system for concrete structures according to claim 1, characterized in that: The external formwork system for concrete structures also includes a third telescopic unit (500), one end of which is hinged to a horizontal force-bearing component (100), and the other end is provided with a third hinge seat (510). The third hinge seat (510) and the first hinge seat (110) are used to fix the existing concrete structure to the side.

3. The external formwork system for concrete structures according to claim 1 or 2, characterized in that: The template unit (400) includes a plurality of template components (410), which can be assembled in the length direction and / or height direction; The external formwork system for concrete structures also includes a backing unit (600), which is detachably connected to the formwork unit (400), and the first telescopic unit (200) and the second telescopic unit (300) are hinged to the backing unit (600).

4. The external formwork system for concrete structures according to claim 3, characterized in that: The back beam unit (600) is used to adjust multiple template units (400) onto the same vertical plane; The template assembly (410) includes a template body (411) and template crossbeams (412) and template longitudinal beams (413) disposed on the template body (411). The template crossbeams (412) and template longitudinal beams (413) are fixed on the template body (411) in a grid pattern. The back beam unit (600) includes at least two sets of back beams (610), each set of back beams (610) includes two, and the two back beams (610) in each set are spaced apart above and below the same template beam (412); a first connecting block (620) can also be detachably connected to the back beams (610) in each set, the first connecting block (620) is used to limit the distance between the two back beams (610) in each set in the height direction; The first telescopic unit (200) and the second telescopic unit (300) are hinged to a second connecting block (210) at one end near the template unit (400), and the second connecting block (210) is detachably connected to the first connecting block (620); The external formwork system for concrete structures also includes a clamping unit (700) for clamping the formwork unit (400) against the back beam (610).

5. The external formwork system for concrete structures according to claim 4, characterized in that: The clamping unit (700) includes a center plate (710) and two clamping plates (720) spaced apart along the height direction. The first ends of the two clamping plates (720) are detachably connected to the template beam (412). The center plate (710) is inserted between the two clamping plates (720) by the second ends of the two clamping plates (720) and is fixedly connected to the two clamping plates (720). The center plate (710) is provided with a wedge hole, and a wedge plate (740) is inserted into the wedge hole. The wedge plate (740) moves downward in the wedge hole to pull the template unit (400) against the template beam (412).

6. The external formwork system for concrete structures according to claim 5, characterized in that: The template assembly (410) is connected in the length direction by connecting bolts.

7. The external formwork system for concrete structures according to claim 5, characterized in that: The back beam (610) is a channel steel.

8. The external formwork system for concrete structures according to claim 1, characterized in that: The first telescopic unit (200), the second telescopic unit (300) and the third telescopic unit (500) each include a screw (220) and a connecting part (230). The two ends of the screw (220) have reverse threads, and the two connecting parts (230) are respectively screwed onto the screw (220).

9. The external formwork system for concrete structures according to claim 1, characterized in that: A second pull rope (640) is connected between the first telescopic unit (200) and the horizontal force-bearing component (100), and a third pull rope (670) is connected between the second telescopic unit (300) and the horizontal force-bearing component (100).

10. The external formwork system for concrete structures according to claim 4, characterized in that: The horizontal force-bearing component (100) is a horizontal frame. The first telescopic unit (200) and the second telescopic unit (300) are arranged in several groups along the length direction of the horizontal force-bearing component (100). Several groups of the first telescopic unit (200) and the second telescopic unit (300) are installed on the same back beam unit (600).

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