CN115288335B

CN115288335B - Prestress single-layer bidirectional cable mesh mounting structure

Info

Publication number: CN115288335B
Application number: CN202210788619.8A
Authority: CN
Inventors: 张富森; 陈敏; 周宇; 江深浩; 林逸恒; 王佛来; 邱俊新
Original assignee: Guangdong Fourth Construction Engineering Co ltd
Current assignee: Guangdong Fourth Construction Engineering Co ltd
Priority date: 2022-07-06
Filing date: 2022-07-06
Publication date: 2023-05-09
Anticipated expiration: 2042-07-06
Also published as: CN115288335A

Abstract

The utility model relates to a prestressing force spatial structure construction technical field especially relates to a prestressing force individual layer bidirectional cable net mounting structure, it includes two concrete columns that are vertical setting, the transverse cable, erect the cable, the regulation box is pre-buried to install of lateral wall that two concrete columns are mutual towards, the regulating disk is installed to the regulating box internal rotation, the both ends of transverse cable respectively with the cambered surface fixed connection who is located the regulating disk of two concrete column departments, install spacing subassembly in the regulating box, the steel truss that is the level setting is commonly fixed mounting at the top of two concrete columns, the one end and the steel truss fixed connection of erect the cable, the reaction device is installed to the other end of erect the cable, the mount that is the level setting is commonly fixed mounting in the bottom of two concrete columns, cross cable anchor clamps are installed to the crossing point department of transverse cable and perpendicular cable, the spider is installed to one side of cross cable anchor clamps. This application has the effect that improves the convenience of staff's installation cable in high altitude environment.

Description

Prestress single-layer bidirectional cable mesh mounting structure

Technical Field

The application relates to the technical field of construction of prestressed space structures, in particular to a prestressed single-layer bidirectional cable net mounting structure.

Background

The cable net mounting structure is generally applied to the mounting of curtain walls, and is one of the common means for mounting glass curtain walls in the modern society.

In the related art, a cable net installation structure curtain wall depends on a stainless steel cable as a main stress rod piece, and a glass panel is fixed on the cable through a stainless steel clamp. The stainless steel inhaul cable is divided into a bearing cable and a stabilizing cable, the bearing cable is laid and assembled in the field firstly, then the hydraulic jack is utilized to continuously pull and lift the bearing cable, anchoring is carried out when the cable head reaches the anchoring point of the ring truss, and then the stabilizing cable is stretched until all anchoring of the inhaul cable is completed, and the structure is formed. Compared with the conventional aluminum alloy curtain wall, the cable net curtain wall has the greatest characteristic of having larger deflection which is changed constantly, and the larger the deflection is, the larger the axial force is caused by the guy cable, so that the generated axial force is exactly used for resisting wind load, gravity load and other loads.

With respect to the related art described above, the inventor considers an installation manner in which a hydraulic jack is used to pull a cable to tighten the cable, and frequent use of the jack is required to tighten a plurality of cables, thereby requiring frequent use and transfer of the jack by a worker in a high-altitude environment, which is very inconvenient.

Disclosure of Invention

In order to improve the convenience of staff's installation cable in the high altitude environment, this application provides a prestressing force individual layer two-way cable net mounting structure.

The application provides a prestressing force individual layer two-way cable net mounting structure adopts following technical scheme:

the utility model provides a two-way cable net mounting structure of prestressing force individual layer, includes two concrete columns, horizontal cable, the perpendicular cable that are vertical setting, its characterized in that: the two concrete columns are mutually oriented's lateral wall pre-buried installs the regulating box, the regulating box internal rotation is installed the regulating disk, the both ends of horizontal cable respectively with be located two the cambered surface fixed connection of regulating disk of concrete column department, install spacing subassembly in the regulating box, spacing subassembly is used for restricting the regulating disk rotates along one-way, two the top of concrete column is fixed mounting jointly has the steel truss that is the level setting, the one end of perpendicular cable with steel truss fixed connection, the reaction device is installed to the other end of perpendicular cable, two the bottom of concrete column is fixed mounting jointly and is the mount that the level set up, reaction device be used for with mount fixed connection, horizontal cable with cross cable anchor clamps are installed to perpendicular intersect department of cable, cross cable anchor clamps's one side is installed and is refuted the claw, refuted the claw and be used for the fixed mounting curtain.

Through adopting above-mentioned technical scheme, spacing subassembly's setting for the staff can realize the tensioning setting to the transverse cable through rotating the regulating disk, and counterforce device's setting makes the staff can carry out tensioning regulation to perpendicular cable on ground, thereby can both save the use to hydraulic jack, thereby has improved the convenience of staff's installation cable in high altitude environment.

Optionally, the spacing subassembly includes the stopper, the stopper is preset the bottom of adjusting the box inner top wall, just the stopper is kept away from one side lateral wall of adjusting box open-ended with the interior roof of adjusting the box articulates the setting, the lateral wall fixed mounting of adjustment dish has the toothed disc, the toothed disc with the stopper is kept away from the one end of adjusting the box meshes mutually.

Through adopting above-mentioned technical scheme, the setting of stopper for gear disk and stopper joint cooperation, thereby realized the rotation of regulating disk, and then realized the rolling to the transverse cable.

Optionally, the coaxial fixedly connected with pivot of lateral wall of regulating disk, the other end of pivot with the lateral wall of regulating box rotates to be connected, the regulating disk is kept away from square blind hole has been seted up to one side of pivot, the regulating box is kept away from one side of pivot runs through to the through-hole has been seted up to the lateral wall of concrete column, just the through-hole with the direction blind hole is aimed at each other.

Through adopting above-mentioned technical scheme, during the regulation, the staff can insert adjusting tool in square blind hole through the through-hole, cooperatees with the direction blind hole, then rotates adjusting tool and drives the regulation and coil the pivot and rotate to make the winding of transverse cable in the regulating plate, realize the tensioning regulation to the transverse cable.

Optionally, the reaction device includes the reaction post, the reaction post is vertical fixing the top of mount, the lateral wall of reaction post is provided with barb portion along vertical direction range, the bottom fixedly connected with sleeve pipe of perpendicular cable, the spout has been seted up to sheathed tube inside wall, slidable mounting has the joint piece in the spout, the joint piece be used for with barb portion joint cooperation, just the joint piece is kept away from one side of perpendicular cable is provided with the direction inclined plane, be provided with the spring in the spout, the one end of spring with the lateral wall fixed connection of joint piece, just the elasticity direction of spring with the direction of movement of joint piece is the same.

Through adopting above-mentioned technical scheme, during the installation, with sleeve pipe and counter-force post regulation to make joint piece and barb portion joint cooperation, and support tightly under the elasticity effect of spring, realized counter-force device.

Optionally, the fit pipe is installed to sheathed tube outside screw thread, the spout link up the sheathed tube lateral wall, the spring keep away from the one end of joint piece with the inside wall looks butt of fit pipe.

Through adopting above-mentioned technical scheme, the setting of cooperation pipe can be through dismantling the cooperation pipe to realize the dismantlement to spring and joint piece, and then realize the dismantlement between sleeve pipe and the counter-force post.

Optionally, the outer side wall of the sleeve is fixedly provided with a gripping block, the gripping block is located below the matching pipe, and the width of the gripping block is larger than that of the matching pipe.

Through adopting above-mentioned technical scheme, the setting of gripping the piece, the person of facilitating the use dismantles sleeve pipe and cooperation pipe through gripping the piece.

Optionally, the gear plate is provided with two, two the gear plate install respectively in the both sides of adjustment disk, the stopper orientation one side of adjustment box open-ended is provided with the cooperation inclined plane, the cooperation inclined plane be used for with the tooth looks butt of gear plate, and two the gear plate all with the stopper is kept away from the one end of adjustment box meshes mutually.

Through adopting above-mentioned technical scheme, the setting of two toothed tables can improve and carry out unidirectional rotation complex stability between regulating plate and the stopper.

Optionally, the cross cable anchor clamps include the fixed plate, one side fixed mounting of fixed plate has ohmic type splint, ohmic type splint be used for with erect the cable cup joint fixedly, the opposite side of fixed plate is provided with the mounting panel, the bottom of mounting panel with the fixed plate is articulated, the top of mounting panel with the fixed plate passes through bolt fixed connection, the mounting panel with the fixed plate cooperation is used for pressing from both sides tightly the transverse cable.

Through adopting above-mentioned technical scheme, during the installation, establish ohmic type splint cover on erecting the cable earlier, then slide cross cable anchor clamps, remove the crossing point department of horizontal cable and erecting the cable, fix horizontal cable through the cooperation of rotation mounting panel fixed plate, realized the tight fixed action of clamp of cross cable anchor clamps.

Optionally, a first planting sub-box and a second planting sub-box are respectively installed on one side, facing the outside, of the side wall of the vertical direction of each two adjacent curtain walls, and the first planting sub-box and the second planting sub-box are mutually spliced to form a planting box.

Through adopting above-mentioned technical scheme, plant the setting of box, can plant green planting in planting box inside to be favorable to the afforestation to the environment, also can carry out cyclic utilization to the rainwater through green planting simultaneously, played environmental protection and energy saving's effect.

Optionally, two adjacent the lateral wall of the vertical direction of curtain installs first L template and second L template respectively towards inside one side, first L template with second L template splices each other and is used for forming the water drainage tank, just the lateral wall of curtain runs through to the wash port has been seted up in the water drainage tank.

Through adopting above-mentioned technical scheme, the setting of water drainage tank can be discharged the rainwater, still can set up through the cooperation of water drainage tank and wash port simultaneously, carries out the moisturizing to vertical planting box.

In summary, the present application includes at least one of the following beneficial technical effects:

1. the setting of the limiting component enables a worker to realize tensioning setting of the transverse inhaul cable by rotating the adjusting disc, and the setting of the counter-force device enables the worker to carry out tensioning adjustment on the vertical inhaul cable on the ground, so that the use of a hydraulic jack can be omitted, and the convenience of installing the inhaul cable in a high-altitude environment by the worker is improved;

2. the arrangement of the matching pipe can realize the disassembly of the spring and the clamping block by disassembling the matching pipe, thereby realizing the disassembly between the sleeve and the counter-force column;

3. the setting of planting the box can plant green planting in planting the box inside to be favorable to the afforestation to the environment, also can carry out cyclic utilization to the rainwater through green planting simultaneously, played environmental protection and energy saving's effect.

Drawings

Fig. 1 is a schematic diagram of an overall structure of a prestressed single-layer bidirectional cable net mounting structure according to an embodiment of the present application.

Fig. 2 is a schematic partial structural cross-sectional view of another view of a prestressed single-layer bidirectional cable web mounting structure according to an embodiment of the present application.

Fig. 3 is an enlarged view of a portion a in fig. 2.

Fig. 4 is an enlarged view of a portion B in fig. 2.

FIG. 5 is a schematic structural view of a cross-shaped cable clamp in an embodiment of the present application

Reference numerals illustrate:

1. a concrete column; 2. a transverse inhaul cable; 3. a vertical inhaul cable; 4. an adjustment box; 5. an adjusting plate; 51. square blind holes; 6. a limit component; 61. a limiting block; 611. matching with the inclined plane; 62. a gear plate; 63. a rotating shaft; 7. a steel truss; 8. a reaction force device; 81. a reaction column; 811. a barb portion; 82. a sleeve; 83. a clamping block; 831. a guide slope; 84. a spring; 85. a mating tube; 9. a fixing frame; 10. a cross guy cable clamp; 101. a fixing plate; 102. an ohmic splint; 103. a mounting plate; 104. a sleeve plate; 11. a spider claw; 12. a planting box; 121. a first type of plant box; 122. a second plant box; 13. a drainage channel; 131. a first L-shaped plate; 132. a second L-shaped plate; 14. curtain walls; 15. a grip block; 16. and (5) a sleeve plate.

Detailed Description

The present application is described in further detail below in conjunction with figures 1-4.

The embodiment of the application discloses a prestress single-layer bidirectional cable net mounting structure. Referring to fig. 1-3, a prestress single-layer bidirectional cable net mounting structure comprises two concrete columns 1, a transverse cable 2 and a vertical cable 3 which are vertically arranged. The lateral wall that two concrete columns 1 face each other all pre-buried install adjusting box 4, and adjusting box 4 is the opening setting towards the lateral wall of another concrete column 1. And be provided with a plurality of regulation boxes 4 on the same concrete column 1, a plurality of regulation boxes 4 are the range setting along vertical direction. The regulating box 4 is rotationally provided with a regulating disc 5, two ends of the transverse inhaul cable 2 are respectively fixedly connected with cambered surfaces of the regulating disc 5 positioned at the two concrete columns 1, the regulating box 4 is internally provided with a limiting component 6, and the limiting component 6 is used for limiting the regulating disc 5 to rotate along a single direction.

Referring to fig. 2-3, the limiting component 6 includes a limiting block 61, the limiting block 61 is preset at the bottom of the inner top wall of the adjusting box 4, and a side wall of the limiting block 61 far away from the opening of the adjusting box 4 is hinged with the inner top wall of the adjusting box 4. The gear plates 62 are fixedly mounted on the two side walls of the adjusting plate 5 respectively, a matching inclined surface 611 is arranged on one side of the limiting block 61 facing the opening of the adjusting box 4, the matching inclined surface 611 is used for being abutted against the meshing teeth of the gear plates 62, and the two gear plates 62 are meshed with one end of the limiting block 61 away from the adjusting box 4. The coaxial fixedly connected with pivot 63 of lateral wall of regulating disk 5, the other end of pivot 63 rotates with the lateral wall of adjusting box 4 to be connected, and square blind hole 51 has been seted up to one side that shaft 63 was kept away from to regulating disk 5, and the through-hole has been seted up to the lateral wall of concrete column 1 to one side that shaft 63 was kept away from to adjusting box 4, and through-hole and direction blind hole are mutually aligned. During adjustment, a worker can insert a tool matched with the square blind hole 51 through the through hole, and drive the adjusting disc 5 to rotate through the tool, and under the configuration effect of the limiting block 61, the adjusting discs 5 at two ends of the transverse inhaul cable 2 tighten the transverse inhaul cable 2 respectively, so that the adjustment of the transverse inhaul cable 2 is realized.

Referring to fig. 1 and 2, the tops of two concrete columns 1 are fixedly provided with a steel truss 7 which is horizontally arranged, one end of a vertical cable 3 is fixedly connected with the steel truss 7, the other end of the vertical cable 3 is provided with a counterforce device 8, and the bottoms of the two concrete columns 1 are fixedly provided with a fixing frame 9 which is horizontally arranged. In this embodiment, a plurality of vertical cables 3 are provided, and the plurality of vertical cables 3 are arranged in a line along the length direction of the steel truss 7. The plurality of vertical inhaul cables 3 are used for being matched with the plurality of horizontal inhaul cables 2 for fixing the curtain wall 14.

Referring to fig. 2 and 4, the reaction force device 8 includes a reaction force column 81, the reaction force column 81 is vertically fixed to the top of the fixing frame 9, the side wall of the reaction force column 81 is provided with a barb portion 811 arranged in the vertical direction, and the bottom end of the vertical cable 3 is fixedly connected with a sleeve 82. In this embodiment, four sliding grooves are formed in the same sleeve 82, and the four sliding grooves are symmetrically arranged in pairs along the central axis of the sleeve. The sliding block 83 is slidably mounted in the sliding groove, the clamping block 83 is used for being matched with the barb 811 in a clamping mode, and a guide inclined surface 831 is arranged on one side, away from the vertical inhaul cable 3, of the clamping block 83, so that the clamping block 83 and the barb 811 can be conveniently clamped. A spring 84 is arranged in the chute, one end of the spring 84 is fixedly connected with the side wall of the clamping block 83, and the elastic direction of the spring 84 is the same as the moving direction of the clamping block 83. During installation, the sleeve 82 is in plug-in fit with the reaction column 81, so that the clamping block 83 and the barb 811 are clamped with each other, and the sleeve 82 is fixed to the reaction column 81, thereby realizing tensioning installation of the vertical stay cable 3.

Referring to fig. 4, in order to facilitate the disassembly of the sleeve 82, a fitting pipe 85 is mounted on the outer thread of the sleeve 82, a chute penetrates the outer side wall of the sleeve 82, and one end of the spring 84 away from the clamping block 83 abuts against the inner side wall of the fitting pipe 85. The outer side wall of the sleeve 82 is fixedly provided with a gripping block 15, the gripping block 15 is located below the matching tube 85, and the width of the gripping block 15 is larger than that of the matching tube 85. Therefore, after the fitting pipe 85 is detached, the spring 84 and the clamping block 83 can be taken out from the chute, so that the vertical stay rope 3 is detached, and the curtain wall 14 can be detached and installed conveniently.

Referring to fig. 2 and 5, a cross cable clamp 10 is installed at the intersection point of the transverse cable 2 and the vertical cable 3, the cross cable clamp 10 includes a fixing plate 101, one side of the fixing plate 101 is fixedly provided with an ohmic clamp plate 102, the ohmic clamp plate 102 is used for sleeving and fixing the vertical cable 3, in this embodiment, the ohmic clamp plate 102 and the fixing plate 101 are fixed through bolts, and thus the vertical cable 3 can be clamped and fixed through the ohmic clamp plate 102 and the fixing plate 101. The opposite side of fixed plate 101 is provided with mounting panel 103, and the bottom of mounting panel 103 is articulated with fixed plate 101, and the top of mounting panel 103 passes through bolt fixed connection with fixed plate 101, and mounting panel 103 cooperates with fixed plate 101 and is used for pressing from both sides tight transverse cable 2. In this embodiment, two mounting plates 103 are disposed on the same fixing plate 101, and a sleeve plate 16104 is disposed between the two mounting plates 103, the sleeve plate 16104 is used for sleeving the transverse cable 2, and a connection claw 11 is mounted on one side of the sleeve plate 16104 away from the cross cable fixture 10, and the connection claw 11 is used for fixedly mounting the curtain wall 14.

Referring to fig. 1 and 2, first and second planting sub-boxes 121 and 122 are respectively installed at sides of the vertical direction sidewalls of the adjacent curtain walls 14 toward the outside, and the first and second planting sub-boxes 121 and 122 are spliced with each other to form the planting box 12. The first L-shaped plate 131 and the second L-shaped plate 132 are respectively installed on one side, facing the inside, of the side walls of the vertical directions of the two adjacent curtain walls 14, the first L-shaped plate 131 and the second L-shaped plate 132 are mutually spliced to form the drainage groove 13, and the side walls of the curtain walls 14 penetrate through to the drainage groove 13 to form drainage holes. Thereby can plant green planting in planting groove, be favorable to the afforestation environment, also can be through planting the cooperation of box 12 and water drainage tank 13 simultaneously in rainy day for ponding in the box 12 flows to water drainage tank 13 through the wash port, and discharges at the guide of water drainage tank 13, can carry out the moisturizing to vertical planting box 12 along the way in the process of discharging, keeps planting the moisture in the box 12.

The implementation principle of the prestress single-layer bidirectional cable mesh mounting structure is as follows:

during installation, tensioning adjustment is carried out on the transverse cable 2 through the limiting component 6, then tensioning adjustment is carried out on the vertical cable 3 through the counter-force component, and then the cross cable clamp 10 is installed at the intersection point of the transverse cable 2 and the vertical cable 3, so that fixed installation of the curtain wall 14 is achieved, the work of tensioning adjustment on the transverse cable 2 and the vertical cable 3 by using a hydraulic jack by workers is omitted, and convenience of installing cables in a high-altitude environment by workers is improved.

The foregoing are all preferred embodiments of the present application, and are not intended to limit the scope of the present application in any way, therefore: all equivalent changes in structure, shape and principle of this application should be covered in the protection scope of this application.

Claims

1. The utility model provides a two-way cable net mounting structure of prestressing force individual layer, includes that two are concrete column (1), horizontal cable (2), the perpendicular cable (3) of vertical setting, its characterized in that: two concrete columns (1) are mutually oriented lateral wall pre-buried install regulating box (4), regulating box (4) internally rotate install regulating plate (5), the both ends of transverse cable (2) respectively with be located two cambered surface fixed connection of regulating plate (5) of concrete column (1) department, install spacing subassembly (6) in regulating box (4), spacing subassembly (6) are used for restricting regulating plate (5) rotate along one-way, two steel truss (7) that are the level setting are installed to the top fixed mounting of concrete column (1) jointly, the one end of perpendicular cable (3) with steel truss (7) fixed connection, counter-force device (8) are installed to the other end of perpendicular cable (3), two the bottom fixed mounting that is the level setting jointly of concrete column (1) mount (9), counter-force device (8) be used for with mount (9) fixed connection, cross anchor clamps (10) are installed in cross anchor clamps (10) of perpendicular crossing point (3), counter-force device (11) are connected with counter-force cable (10), counter-force device (11) are connected to one side of connecting counter-force cable (11), the utility model discloses a fixing rack, including fixing rack (9) and counter-force post (81), counter-force post (81) are vertical fixing rack (9) top, the lateral wall of counter-force post (81) is arranged along vertical direction and is provided with barb portion (811), the bottom fixedly connected with sleeve pipe (82) of perpendicular cable (3), the spout has been seted up to the inside wall of sleeve pipe (82), slidable mounting has joint piece (83) in the spout, joint piece (83) be used for with barb portion (811) joint cooperation, just joint piece (83) are kept away from one side of perpendicular cable (3) is provided with direction inclined plane (831), be provided with spring (84) in the spout, one end of spring (84) with the lateral wall fixed connection of joint piece (83), just the elasticity direction of spring (84) with the direction of movement of joint piece (83) is the same.

2. The prestress single-layer bidirectional cable mesh mounting structure according to claim 1, wherein: limiting component (6) are including stopper (61), stopper (61) are preset the bottom of roof in adjusting box (4), just stopper (61) are kept away from one side lateral wall of adjusting box (4) open-ended with the interior roof of adjusting box (4) articulates the setting, the lateral wall fixed mounting of adjusting disk (5) has toothed disc (62), toothed disc (62) with stopper (61) are kept away from the one end of adjusting box (4) meshes mutually.

3. The prestressed single-layer bidirectional cable web installation structure according to claim 2, wherein: the side wall coaxial fixedly connected with pivot (63) of regulating disk (5), the other end of pivot (63) with the lateral wall rotation of regulating box (4) is connected, square blind hole (51) have been seted up to one side that regulating disk (5) kept away from pivot (63), regulating box (4) keep away from one side of pivot (63) runs through to the lateral wall of concrete column (1) has been seted up the through-hole, just the through-hole with direction blind hole is aimed at each other.

4. The prestress single-layer bidirectional cable mesh mounting structure according to claim 1, wherein: the outside screw thread of sleeve pipe (82) is installed cooperation pipe (85), the spout link up the lateral wall of sleeve pipe (82), one end that spring (84) kept away from joint piece (83) with the inside wall butt of cooperation pipe (85).

5. The prestress single-layer bidirectional cable mesh mounting structure of claim 4, wherein: the outer side wall of the sleeve (82) is fixedly provided with a gripping block (15), the gripping block (15) is located below the matching pipe (85), and the width of the gripping block (15) is larger than that of the matching pipe (85).

6. The prestressed single-layer bidirectional cable web installation structure according to claim 2, wherein: the gear plate (62) is provided with two, two gear plates (62) install respectively in the both sides of adjustment dish (5), stopper (61) orientation one side of adjustment box (4) open-ended is provided with cooperation inclined plane (611), cooperation inclined plane (611) be used for with the tooth looks butt of gear plate (62), and two gear plate (62) all with stopper (61) are kept away from the one end of adjustment box (4) is meshed.

7. The prestress single-layer bidirectional cable mesh mounting structure according to claim 1, wherein: the cross cable clamp (10) comprises a fixing plate (101), one side of the fixing plate (101) is fixedly provided with an ohmic clamping plate (102), the ohmic clamping plate (102) is used for being sleeved and fixed with a vertical cable (3), the other side of the fixing plate (101) is provided with a mounting plate (103), the bottom of the mounting plate (103) is hinged to the fixing plate (101), the top of the mounting plate (103) is fixedly connected with the fixing plate (101) through bolts, and the mounting plate (103) is matched with the fixing plate (101) to clamp a transverse cable (2).

8. The prestress single-layer bidirectional cable mesh mounting structure according to claim 1, wherein: a first planting sub-box (121) and a second planting sub-box (122) are respectively arranged on one side, facing the outside, of the side walls of the vertical directions of two adjacent curtain walls (14), and the first planting sub-box (121) and the second planting sub-box (122) are mutually spliced to form a planting box (12).

9. The prestressed single-layer bidirectional cable web installation structure according to claim 8, wherein: two adjacent side walls of the vertical direction of the curtain wall (14) are respectively provided with a first L-shaped plate (131) and a second L-shaped plate (132) towards one side of the inside, the first L-shaped plate (131) and the second L-shaped plate (132) are mutually spliced to form a drainage groove (13), and the side walls of the curtain wall (14) penetrate through to the drainage groove (13) and are internally provided with drainage holes.