Drainage head cleaning clamp
By designing a drain head cleaning clamp, and utilizing the combination structure of the hook and auxiliary parts, the problem of requiring multiple tools to clean the drain cover and drain head is solved, achieving a highly efficient cleaning effect without tools or manual contact.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- 江舜杰
- Filing Date
- 2025-05-16
- Publication Date
- 2026-04-28
AI Technical Summary
In the existing technology, cleaning drain covers and drain heads requires the use of multiple tools and manual operation, which is unhygienic and inconvenient.
Design a drain cleaning clamp, including a clamp body, a fixed part, a movable part, a hook part, and an auxiliary part. The hook part hooks the drain cover, the auxiliary part pries the drain head away, and the movable part holds and rinses it, achieving operation without multiple tools and hand contact.
It enables efficient cleaning of drain covers and drain heads without the need for multiple tools or manual contact, improving the convenience and hygiene of cleaning, and is suitable for drainage components of various shapes and weights.
Smart Images
Figure CN224168286U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to clamps, and in particular to a drain head cleaning clamp. Background Technology
[0002] Generally, a drain pipe is buried underground and extends upwards to the surface to form its inlet. The inlet is typically covered by a drain cover with several spaced-apart baffles to initially filter out hair, dust, dander, and other debris and dirt flowing into the inlet with the tap water. A drain head is usually installed near the inlet of the drain pipe to further filter out any debris and dirt that is not blocked by the drain cover and flows into the inlet with the tap water. This prevents the accumulation of such debris and dirt in the drain pipe in a short period, thus avoiding a decrease in the flow rate of the tap water. Even though the baffle holes of the drain cover can initially filter residue and dirt, and the drain head can further filter dander, hair, dust, etc., it is well known that excessive accumulation of residue and dirt on the drain cover or inside the drain head will affect the flow rate of tap water into the drain pipe. Furthermore, the residue and dirt accumulated in the drain head can breed mold that is harmful to human health. To avoid affecting the flow rate of tap water into the drain pipe, the general public should clean the drain cover and drain head regularly.
[0003] When cleaning the drain cover and faucet, most people use a flathead screwdriver to pry open or remove them, then manually or with tweezers, place them in the sink or above the toilet for washing. Therefore, each time they handle the drain cover and faucet with their bare hands, their hands inevitably come into contact with residue, dirt, and mold, resulting in poor hygiene. Even with tweezers, which avoids handling the drain cover and faucet with bare hands, it's difficult to easily grasp the cylindrical faucet valve or the ball handle of the baffle plate with one hand, or support the faucet and baffle plate while rinsing with a stream of water with the other. Furthermore, the flathead screwdriver is still needed when removing the drain cover and faucet. Therefore, each cleaning process requires the use of different tools, such as a flathead screwdriver and tweezers, and is quite inconvenient during rinsing.
[0004] As explained above, improving the cleaning tools for drain heads to make them easier for the general public to clean is a problem that needs to be solved by relevant businesses in this technical field. Utility Model Content
[0005] The purpose of this utility model is to provide a drain cleaning clamp that makes it convenient for the general public to clean drain heads.
[0006] The present invention relates to a drain head cleaning clamp, comprising a clamp body, which is integrally formed. The clamp body includes a fixed part, two movable parts, two hook parts, and an auxiliary part.
[0007] The fixing part is plate-shaped and has a top and bottom end arranged oppositely.
[0008] The two movable parts are each plate-shaped and have opposite upper and lower edges, and a connecting area connecting the upper and lower edges. The upper edges of the two movable parts are connected to each other and attached to the bottom end of the fixed part, and the two connecting areas extend from their respective upper edges away from the top end of the fixed part at intervals.
[0009] The two hook-holding parts are each plate-shaped and connected to the lower edge of their respective movable parts. Furthermore, each hook-holding part forms an angle with its corresponding connecting area.
[0010] The auxiliary part is in the form of a thin sheet and extends from the top end of the fixing part toward the bottom end. The auxiliary part has a thickness that decreases from the top end of the fixing part toward the bottom end.
[0011] The present invention relates to a drain head cleaning clamp, wherein the connecting areas of each movable part have upper and lower sections that are connected to each other, and the upper and lower sections of each connecting area form an obtuse angle with each other, and the angle between each hook part and its corresponding connecting area is less than the obtuse angle.
[0012] The present invention provides a drain head cleaning clamp, wherein the clamp body further includes two sets of reinforcing ribs, each set of reinforcing ribs being respectively disposed on each of the movable parts and each of the hook parts, and the two sets of reinforcing ribs protruding from the opposite outer surfaces of the two movable parts and the two hook parts in opposite directions.
[0013] The drain head cleaning clamp of this utility model includes each reinforcing rib group having two first ribs, several second ribs, and a third rib. The two first ribs of each reinforcing rib group are connected to each other by their respective hook portions and the ends away from the movable portion, and extend towards the movable portion at intervals. The second ribs of each reinforcing rib group extend towards their respective hook portions at intervals from their respective movable portions and near the junction of the upper and lower sections, so as to partially connect to their respective two first ribs. The third ribs of each reinforcing rib group are annular and located in their respective movable portions and near the junction of the upper and lower sections, and are spaced apart from the second ribs.
[0014] The present invention provides a drain head cleaning clamp, wherein the clamp body further includes two clamping ribs, each clamping rib being respectively disposed on each hook portion, and the two clamping ribs being protruding from the bottom of the inner surface of the corresponding hook portion facing each other.
[0015] The drain head cleaning clamp of this utility model has two hooks with their inner surfaces facing each other, each having a groove that is recessed toward its corresponding outer surface.
[0016] The present invention relates to a drain head cleaning clamp, wherein the clamp body further includes a hook mouth portion, the hook mouth portion being plate-shaped and extending from the top end adjacent to the fixing portion first toward the two hook holding portions in the same direction and then toward the bottom end of the fixing portion.
[0017] The present invention discloses a drain head cleaning clamp, wherein the clamp body further includes two reinforcing rib groups and two clamping rib groups correspondingly connected to each of the reinforcing rib groups. Each reinforcing rib group is correspondingly disposed on each of the movable parts and protrudes from opposite ends of the inner surfaces of the corresponding movable parts. Each clamping rib group is correspondingly disposed on each of the hook parts and protrudes from opposite ends of the inner surfaces of the corresponding hook parts.
[0018] The present invention relates to a drain head cleaning clamp, wherein each reinforcing rib group has two first ribs, several second ribs, and a third rib; the two first ribs of each reinforcing rib group are connected to each other at their respective hook portions and at their ends away from the movable portion, and extend toward the movable portion at intervals, with the first ribs located at the bottom edge of their respective hook portions; the second ribs of each reinforcing rib group extend toward their respective hook portions at intervals from their respective movable portions and near the junction of the upper and lower sections, to partially connect to their respective two first ribs; the third ribs of each reinforcing rib group are annular and located at their respective movable portions and near the junction of the upper and lower sections, spaced apart from the second ribs.
[0019] The beneficial effects of this utility model are that it can hook the drain cover with the two hooks of the clamp body, and can also pry the drain head away from the inlet of the drain pipe with the auxiliary part of the clamp body before clamping the drain head with the two hooks. It can also hold the drain head with the two hooks and the movable part for direct rinsing without the need for different tools or hand touch, making it more convenient to use. For drain head components with built-in screws, the auxiliary part can be used as a flathead screwdriver to turn the screws off. In addition, the two movable parts and the two hooks can also hold the drain cover or interceptor plate in the opposite direction for rinsing. Attached Figure Description
[0020] Other features and effects of this utility model will be clearly presented in the embodiments with reference to the accompanying drawings:
[0021] Figure 1A This is a perspective view illustrating the first embodiment of the drain head cleaning clamp of this utility model;
[0022] Figure 1B This is a frontal view diagram illustrating the detailed structure of the first embodiment of this utility model;
[0023] Figure 1C This is a side view diagram illustrating that the angle between the upper and lower sections of the two movable parts of the clamp body in the first embodiment of this utility model is an obtuse angle, and the angle between the two hook parts and the lower section of their respective movable parts is less than the obtuse angle.
[0024] Figure 2 It is a 3D exploded view illustrating the specific structure of the drain head assembly;
[0025] Figure 3 This is a perspective view illustrating the second embodiment of the drain head cleaning clamp of this utility model;
[0026] Figure 4 This is a perspective view illustrating the usage state of the hook mouth portion of the second embodiment of this utility model hooking up the small drainage hole of the elongated drainage cover;
[0027] Figure 5 This is a perspective view illustrating the usage state of the head of the plastic intercepting sheet being embedded in the grooves at the two hook-holding portions of the second embodiment of this utility model;
[0028] Figure 6 This is a perspective view illustrating the usage state of using the two movable parts and the two hook parts of the second embodiment of this utility model to clamp and lift the water gate;
[0029] Figure 7 This is a perspective view illustrating the third embodiment of the drain head cleaning clamp of this utility model; and
[0030] Figure 8 This is a perspective view illustrating the fourth embodiment of the drain head cleaning clamp of this utility model. Detailed Implementation
[0031] In the detailed description of this utility model, it should be noted that similar elements are represented by the same reference numerals in the following description.
[0032] See Figure 1A , Figure 1B and Figure 1C A first embodiment of the drain head cleaning clamp of this utility model is used for cleaning a... Figure 2 The drain head assembly 9 is shown. The drain head assembly 9 has a base 91 with a stepped hole 910 mounted on the ground (not shown), a drain head body 92 mounted on the stepped hole 910 of the base 91, and a metal drain cover 93 covering the stepped hole 910 and the drain head body 92 and having several drain holes 930. The drain head cleaning clamp of the first embodiment includes a clamp body C, which is a one-piece molded plastic part manufactured by injection molding technology. The clamp body C includes a fixing part 2, two movable parts 3, two hook parts 4, and an auxiliary part 5.
[0033] The fixing part 2 is plate-shaped and has a top end 21 and a bottom end 22 arranged opposite to each other.
[0034] Each of the two movable parts 3 is plate-shaped and has an upper edge 31 and a lower edge 32 arranged opposite to each other, and a connecting area 33 connecting the upper edge 31 and the lower edge 32. The upper edges 31 of the two movable parts 3 are connected to each other and connected to the bottom end 22 of the fixed part 2, and the connecting areas 33 of the two movable parts 3 extend from their respective upper edges 31 away from the top end 21 of the fixed part 2 at intervals.
[0035] Each of the two hook-holding parts 4 is plate-shaped and connected to the lower edge 32 of its corresponding movable part 3. Each hook-holding part 4 and its corresponding connecting area 33 form an angle α.
[0036] The auxiliary part 5 is in the shape of a thin sheet and extends from the top end 21 of the fixing part 2 toward the bottom end 22. The auxiliary part 5 has a thickness that decreases from the top end 21 of the fixing part 2 toward the bottom end 22.
[0037] When a user needs to clean the residue and dirt (not shown) remaining on the metal drain cover 93 and inside the drain head body 92, the two hook parts 4 of the drain head cleaning clamp of the first embodiment can be inserted into one of the drain holes 930 of the metal drain cover 93 to hook up the metal drain cover 93, and the two movable parts 3 can be used to support it in the opposite direction and place it in a sink (not shown) or above a toilet for rinsing. Next, the auxiliary part 5 of the drain head cleaning clamp of the first embodiment is inserted obliquely to the lower part of the top of the drain head body 92 to abut against the step hole 910 of the base 91. After the drain head body 92 is pried away from the step hole 910 of the base 91, the two hook parts 4 are used to clamp the drain head body 92 into the sink or above the toilet for rinsing. Furthermore, some drain head bodies 92 do not have a closed structure below the cross rib formed in the middle. In this case, the two hook parts 4 can be passed through the gap between the cross ribs and hooked upwards to grab two of the cross ribs, and then lifted into the sink or above the toilet for rinsing. In addition, for the drain head assembly 9 and the metal drain cover 93 with built-in screws (not shown), the auxiliary part 5 can also be used as a flathead screwdriver to unscrew the screws.
[0038] In the first embodiment of this utility model, the connecting area 33 of each movable part 3 has an upper section 331 and a lower section 332 connected to each other, and the upper section 331 and the lower section 332 of each connecting area 33 are within an obtuse angle β. The angle α between each hook part 4 and the lower section 332 of its corresponding connecting area 33 is smaller than the obtuse angle β. Therefore, when the user needs to hook up the metal drain cover 93, there is no need to excessively adjust the angle of the two hook parts 4 when they are inserted into one of the drain holes 930. This allows the user to easily hook up the metal drain cover 93 and also makes it convenient to lift the metal drain cover 93 in the opposite direction for rinsing.
[0039] Furthermore, to enable the user to effectively grip the drain head body 92, the clamp body C also includes two reinforcing rib groups 6 and two clamping ribs 71. Specifically, each reinforcing rib group 6 is correspondingly disposed on each movable part 3 and each hook part 4, and the two reinforcing rib groups 6 protrude from oppositely arranged outer surfaces of the two movable parts 3 and the two hook parts 4. More specifically, in the first embodiment, each reinforcing rib group 6 has two first ribs 61, several second ribs 62, and a third rib 63. The two first ribs 61 of each reinforcing rib group 6 are connected to each other at their respective hook parts 4 and at their ends away from the movable parts 3, and extend towards the movable parts 3 at intervals. The second ribs 62 of each reinforcing rib group 6 extend from their respective movable portions 3, near the junction of the upper segment 331 and the lower segment 332, toward their respective hook portions 4, and are spaced apart from each other, to partially connect to their respective two first ribs 61. The third rib 63 of each reinforcing rib group 6 is annular and located in its respective movable portion 3, near the junction of the upper segment 331 and the lower segment 332, and is spaced apart from the second ribs 62. Each clamping rib 71 is correspondingly disposed in each hook portion 4, and the two clamping ribs 71 protrude from the bottom of an inner surface of their respective hook portions 4 that are facing each other. It can be seen that the two reinforcing ribs 6 help to improve the rigidity when the user holds the two movable parts 3, and the two clamping ribs 71 can increase the clamping area between them and the drain head body 92, making it easier for the user to clamp the drain head body 92.
[0040] See Figure 3A second embodiment of the drain head cleaning clamp of this utility model is generally the same as the first embodiment, except that the thickness of the two hook portions 4 in the second embodiment is greater than that in the first embodiment, and each of the inner surfaces of the two hook portions 4 facing each other in the second embodiment has a groove 40 recessed toward its corresponding outer surface. Furthermore, the clamp body C of the second embodiment also includes a hook mouth portion 8. The hook mouth portion 8 is plate-shaped and first protrudes from the top end 21 near the fixing portion 2 toward the two hook portions 4 in the same direction, and then extends toward the bottom end 22 of the fixing portion 2. Compared to the first embodiment, the structural design of the second embodiment allows the user to maintain the necessary grip strength when clamping the drain head body 92, while further increasing the clamping area between the two hook parts 4 and the drain head body 92 or one end handle 952 of an interceptor plate 95. Furthermore, the two hook parts 4 and the movable part 3 can support the heavier drain head body 92 or a stainless steel water gate 96. The hook tip 8 can also hook up an elongated drain cover 94 with several small drainage holes 940. Several methods of using this second embodiment of the present invention are briefly described below.
[0041] See Figure 4 The diagram shows an elongated drain cover 94 that can be installed at the inlet (not shown) of a drain pipe, and the elongated drain cover 94 is provided with a small drain hole 940. When the two hook parts 4 of the second embodiment cannot be inserted into the small drain hole 940, the user can instead insert the hook mouth part 8 into one of the small drain holes 940 to hook the elongated drain cover 94 away from the inlet of the drain pipe.
[0042] See Figure 5 The display shows a setting for such Figure 2 The metal drain cover 93 shown has an interceptor plate 95 underneath. The interceptor plate 95 includes a radially shaped plate portion 951 and a head handle portion 952 protruding upward from the center of the plate portion 951. The user can also insert the head handle portion 952 of the interceptor plate 95 through the grooves 40 located at the two hook portions 4 in the second embodiment, and move the interceptor plate 95 over the sink or toilet for rinsing.
[0043] See Figure 6 The display shows settings for, such as Figure 2The base 91, with its stepped hole 910, replaces the stainless steel swivel gate 96, which is heavier than the main body 92 of the drain head. When the user needs to clean the stainless steel swivel gate 96, the auxiliary part 5 can be inserted obliquely below the top of the stainless steel swivel gate 96 to abut against the stepped hole 910 of the base 91. After prying the stainless steel swivel gate 96 away from the stepped hole 910, the user can then use the triangular support structure formed by the hooks 4, the movable parts 3, and the stainless steel swivel gate 96 to hook and hold the stainless steel swivel gate 96 together, placing it in the sink or above the toilet for rinsing. Therefore, the user does not need to worry about the hooks 4 being too weak to grip the heavier stainless steel swivel gate 96, nor about the hooks 4 being too weak to withstand the impact of the water jet, achieving a completely hands-free cleaning experience. (See also...) Figure 7 A third embodiment of the drain head cleaning clamp of this utility model is generally the same as the first embodiment, except that the two reinforcing rib groups 6 are positioned differently in the third embodiment. Furthermore, the clamp body C of the third embodiment also includes two clamping rib groups 72 with structures different from the two clamping ribs 71 of the first embodiment. In addition, the thickness of each of the two movable parts 3 and the two hook parts 4 in the third embodiment is less than the thickness of each of the two movable parts 3 and the two hook parts 4 in the first embodiment. Specifically, each clamping rib group 72 in the third embodiment is correspondingly connected to each reinforcing rib group 6. Each reinforcing rib group 6 is correspondingly disposed on each movable part 3, and protrudes from opposite ends of the opposing inner surfaces of the corresponding movable parts 3. Each clamping rib group 72 is correspondingly disposed on each hook part 4, and protrudes from opposite ends of the opposing inner surfaces of the corresponding hook parts 4. Compared to the first embodiment, the structural design of the third embodiment also allows the user to maintain the necessary grip strength when gripping the main body 92 of the drain head, while further increasing the clamping area between the two hook parts 4 and the main body 92 of the drain head, and increasing the space for clamping the head handle part 952 of the interceptor plate 95.
[0044] See Figure 8A fourth embodiment of the drain head cleaning clamp of this utility model is generally the same as the first or second embodiment, except that the two reinforcing rib groups 6 in the fourth embodiment have detailed structures. Specifically, in the fourth embodiment, one of the two first ribs 61 of each reinforcing rib group 6 is located at the bottom edge of its corresponding hook portion 4. It is worth mentioning that the two first ribs 61 of each reinforcing rib group 6 in the fourth embodiment facilitate the collection of hair (not shown) and the scraping of dirt on the metal drain cover 93. The collected hair and dirt can then be picked up and discarded using the two hook portions 4, without touching the user's hands.
[0045] As can be seen from the above detailed description of this utility model, when cleaning the metal drain cover 93 of the drain head assembly 9, the user only needs to hook the metal drain cover 93 with the two hook parts 4 of this embodiment, and use the two movable parts 3 to hold it in the opposite direction and rinse it above the sink or toilet. When cleaning the drain head body 92 or the stainless steel water gate 96 of the drain head assembly 9, the user only needs to use the auxiliary part 5 of this embodiment to first pry the drain head body 92 or the stainless steel water gate 96 away from the step hole 910 of the base 91, and then use the two clamping ribs 71 or the two clamping rib groups 72 located at the two hook parts 4 to clamp the drain head body 92 or the same. When using the two movable parts 3 and the two hook parts 4, the stainless steel water gate 96 can be hooked and held to the top of the sink or toilet for rinsing. When removing the elongated drain cover 94, the hook mouth part 8 can be used to hook it away from the inlet of the drain pipe. When cleaning the plastic interceptor 95, the groove 40 at the two hook parts 4 can be used to insert the head handle part 952 to move it to the top of the sink or toilet for rinsing. There is no need to use different tools or touch the user's hands. It is convenient and hygienic. Furthermore, for the drain head assembly 9 and the metal drain cover 93 with built-in screws, the auxiliary part 5 can be used as a flathead screwdriver to unscrew the screws.
[0046] In summary, the drain head cleaning clamp of this utility model can both hook the metal drain cover 93 using the two hooking parts 4 of the clamp body C, and pry the drain head body 92 or the stainless steel water gate 96 away from the step hole 910 of the base 91 using the auxiliary part 5 of the clamp body C, and then use the two clamping ribs 71 or the two clamping rib groups 72 located at the two hooking parts 4 to clamp the drain head body 92, or simultaneously use the two movable parts 3 to hook and hold the stainless steel water gate 96 with the two hooking parts 4. The grooves 40 at the four locations can be used to embed the head handle 952 of the plastic interceptor plate 95, and the two first ribs 61 of the reinforcing rib assembly 6 facilitate the collection of hair (not shown) and the scraping of dirt on the metal drain cover 93. The collected hair and dirt can be picked up and discarded by the two hooks 4. Furthermore, for the drain head assembly 9 and the metal drain cover 93 with built-in screws, the auxiliary part 5 can be used as a flathead screwdriver to unscrew the screws, making it convenient to use without the need for different tools. Therefore, it can indeed achieve the purpose of this utility model.
[0047] The above description is merely an embodiment of the present utility model and should not be construed as limiting the scope of the present utility model. Any simple equivalent changes and modifications made in accordance with the claims and description of the present utility model shall still fall within the scope of the present utility model.
Claims
1. A drain head cleaning clamp, characterized in that, include: The clamp body is integrally formed and includes: The fixing part is plate-shaped and has an oppositely arranged top and bottom end. The two movable parts are each plate-shaped and have oppositely arranged upper and lower edges and connecting areas connecting the upper and lower edges. The upper edges of the two movable parts are connected to each other and attached to the bottom end of the fixed part. The two connecting areas extend from their respective upper edges away from the top end of the fixed part at intervals. Two hook-holding parts, each plate-shaped, are connected to the lower edge of their respective movable parts, and the angle between each hook-holding part and its corresponding connecting area is... The auxiliary part is in the form of a thin sheet and extends from the top end of the fixing part toward the bottom end, and the auxiliary part has a thickness that decreases from the top end of the fixing part toward the bottom end.
2. The drain head cleaning clamp according to claim 1, characterized in that: The connecting areas of each movable part have upper and lower sections that are connected to each other, and the upper and lower sections of each connecting area form an obtuse angle with each other, and the angle between each hook and its corresponding connecting area is less than the obtuse angle.
3. The drain head cleaning clamp according to claim 2, characterized in that: The clamp body also includes two sets of reinforcing ribs, each set of reinforcing ribs being respectively disposed on each of the movable parts and each of the hook parts, and the two sets of reinforcing ribs protruding from the opposite outer surfaces of the two movable parts and the two hook parts in opposite directions.
4. The drain head cleaning clamp according to claim 3, characterized in that: Each reinforcing rib group has two first ribs, several second ribs, and a third rib; the two first ribs of each reinforcing rib group are connected to each other by their respective corresponding hook portions and the ends away from the movable portion, and extend towards the movable portion at intervals; The second ribs of each reinforcing rib group extend from their respective movable parts and near the junction of the upper and lower sections toward their respective hook parts at intervals, so as to partially connect to their respective two first ribs; the third ribs of each reinforcing rib group are annular and located in their respective movable parts and near the junction of the upper and lower sections, and are spaced apart from the second ribs.
5. The drain head cleaning clamp according to claim 3, characterized in that: The clamp body also includes two clamping ribs, each clamping rib being respectively disposed on each hook portion, and the two clamping ribs being protruding from the bottom of the inner surface of the corresponding hook portion facing each other.
6. The drain head cleaning clamp according to claim 3, characterized in that: The inner surfaces of the two hooks, which are arranged facing each other, are each provided with a groove that is recessed toward their respective outer surfaces.
7. The drain head cleaning clamp according to claim 1, characterized in that: The clamp body also includes a hook mouth portion, which is plate-shaped and extends from the top end adjacent to the fixing portion towards the two hook holding portions in the same direction, and then extends towards the bottom end of the fixing portion.
8. The drain head cleaning clamp according to claim 1, characterized in that: The clamp body further includes two sets of reinforcing ribs and two sets of clamping ribs connected to each set of reinforcing ribs. Each set of reinforcing ribs is disposed on each of the movable parts and protrudes from opposite ends of the inner surfaces of the corresponding movable parts. Each set of clamping ribs is disposed on each of the hook parts and protrudes from opposite ends of the inner surfaces of the corresponding hook parts.
9. The drain head cleaning clamp according to claim 3, characterized in that: Each reinforcing rib group has two first ribs, several second ribs, and a third rib. The two first ribs of each reinforcing rib group are connected to each other at their respective hook portions and at the ends away from the movable portion, and extend towards the movable portion at intervals. The first ribs are located at the bottom edge of their respective hook portions. The second ribs of each reinforcing rib group extend towards their respective hook portions at intervals from their respective movable portions and near the junction of the upper and lower sections, so as to partially connect to their respective two first ribs. The third ribs of each reinforcing rib group are annular and located at their respective movable portions and near the junction of the upper and lower sections, spaced apart from the second ribs.