Plastic particle waste hot melting treatment device
By designing a plastic pellet waste hot melt treatment device that includes hot melt, compression, purification and heat exchange components, the problems of impurities accumulation, incomplete waste gas treatment and rapid condensation of liquid plastics in the plastic waste treatment process in the prior art are solved, and efficient plastic waste treatment and flow stability are achieved.
Patent Information
- Application Number
- CN202510307954.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-14
- Publication Date
- 2025-06-13
AI Technical Summary
During the filtration process, existing plastic waste hot melt treatment devices are prone to problems such as accumulation of impurities, incomplete waste gas treatment and rapid condensation of liquid plastics, which affects the treatment effect.
A hot melt treatment device for plastic pellet waste including hot melt assembly, compression assembly, purification assembly and heat exchange assembly is designed. The hot melt assembly is heated through a heating tube and filters plastic waste on the filter plate. The compression assembly removes impurities on the filter plate, purifies the assembly to process organic waste gas, and the heat exchange assembly increases the heat exchange area of the plastic fluid through the thin tube to prevent solidification.
It realizes efficient filtration and impurity treatment of plastic waste, has integrated waste gas treatment capacity, and prevents rapid condensation of plastic fluids by increasing the heat exchange area, improving the treatment effect.
Smart Images

Figure CN120133285A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to the technical field of plastic waste treatment, and more specifically to a hot melt treatment device for plastic particle waste. Background Art
[0002] The hot melt treatment of plastic waste is an effective method for waste plastic recycling and utilization. The hot melt treatment of plastic waste mainly uses heating to melt the plastic, and through a series of treatment processes, it is converted into plastic products or raw materials that can be used again. However, the hot melt treatment device for plastic waste in the prior art still has the following deficiencies;
[0003] First of all, after the hot melt treatment device for plastic waste in the prior art melts the plastic waste by heating, it is necessary to filter the plastic waste in a liquid state to intercept the solid particle impurities inside. When the filtration is completed, these solid particle impurities will accumulate on the filter plate, which will affect the filtration performance of the device over time;
[0004] Secondly, when the hot melt treatment device for plastic waste in the prior art heats the plastic waste, it will generate waste gas containing organic components. However, the hot melt treatment device for plastic waste in the prior art does not have an integrated waste gas treatment device;
[0005] Finally, when the hot melt treatment device for plastic waste in the prior art filters the melted liquid plastic waste, it essentially refines it into small streams of liquid for transmission and flow. When the plastic waste is divided into small streams, the heat transfer surface area of its fluid increases, resulting in its easy and rapid cooling, and thus gradually solidifying during the transportation process, thereby affecting the filtration and flow effect of the plastic waste;
[0006] Therefore, in order to solve the above problems, a hot melt treatment device for plastic particle waste is needed. Summary of the Invention
[0007] In order to overcome the above-mentioned defects of the prior art, the present invention provides a hot melt treatment device for plastic particle waste to solve the problems existing in the above-mentioned background art.
[0008] The present invention provides the following technical solution: A hot melt treatment device for plastic particle waste, including a hot melt component, a compression component is fixedly installed on one side of the hot melt component, a purification component is fixedly installed on the other side of the hot melt component, and a heat exchange component is fixedly installed at the bottom of the hot melt component;
[0009] The hot-melt assembly includes a hot-melt bin, a bottom plate is fixedly installed at the bottom end of the hot-melt bin, a filter plate is fixedly installed on the bottom plate, a heating pipe is fixedly installed on the inner wall at the bottom end of the hot-melt bin, a movable groove is formed on the inner wall of the hot-melt bin, a channel is formed at the bottom of the movable groove, a movable plate is movably sleeved in the movable groove, an upper end of the movable plate is fixedly connected with a plate shaft, the plate shaft is located in the movable groove, an upper end of the shaft body of the plate shaft is fixedly connected with an opening and closing electric cylinder, when the movable plate is at the lowest end, the channel is closed, an upper plate is fixedly installed at the upper end of the hot-melt bin, a feeding pipe is fixedly connected to the upper end of the upper plate, a connection hole is formed on the upper plate, the opening and closing electric cylinder is fixedly installed on the upper surface of the upper plate, a propulsion electric cylinder is fixedly installed on an outer side surface of the hot-melt bin, a push rod is fixedly connected to a driving end of the propulsion electric cylinder, an arc plate is fixedly connected to a terminal of the shaft body of the push rod, and the arc plate is aligned with the channel and is adapted in length and width.
[0010] Further, the compression assembly includes an arc cylinder, the arc cylinder is fixedly connected to a side end of the bottom plate, the arc cylinder is fixedly connected with a semi-arc member, an embedding groove is formed on the semi-arc member, the embedding groove is adapted to the arc plate, and after the arc plate fits into the embedding groove, it forms a cylinder member with the arc cylinder and the semi-arc member.
[0011] Further, a stacked screw shaft is movably sleeved inside the cylinder member formed by the arc cylinder, a rotating shaft is fixedly sleeved at the center of the stacked screw shaft, a fixing plate is fixedly installed at the front end of the arc cylinder, a compression motor is fixedly installed on the fixing plate, a driving end of the compression motor is fixedly connected to the shaft body of the rotating shaft, a collection box is arranged at the rear end of the arc cylinder, and the collection box is fixedly installed on the outer side surface of the hot-melt bin.
[0012] Further, the purification assembly includes an air box, a blower is fixedly installed on an outer side of the air box, an adsorption plate is fixedly installed inside the air box, the installation height of the adsorption plate is higher than that of the blower, a box plate is fixedly installed at the upper end of the air box, an air pipe is fixedly connected to the box plate, and a pipe end of the air pipe is fixedly connected to the connection hole.
[0013] Further, the heat exchange assembly includes thin tubes, the number of the thin tubes is the same as the number of filter holes on the filter plate, the thin tubes are sequentially connected to the filter holes on the filter plate, a liquid discharge plate is fixedly installed at the bottom end of the thin tubes, and an external connection plate is fixedly installed at an outer end of the liquid discharge plate.
[0014] Further, a heat exchange bin is fixedly installed between the bottom plate and the external connection plate, a liquid inlet pipe is fixedly connected to a lower side of one side of the heat exchange bin, a liquid discharge pipe is fixedly connected to an upper side of the other side of the heat exchange bin, an external connection member is fixedly connected to the bottom of the external connection plate, a liquid discharge port is fixedly installed at the bottom end of the external connection member, connection frames are fixedly installed at both ends of the external connection member, and fixing frames are fixedly connected to bottom ends of the connection frames.
[0015] Technical effects and advantages of the present invention:
[0016] 1. The present invention is provided with a compression component. Plastic waste is put into the hot melt bin from the feeding pipe and heated and melted under the heating of the heating pipe. The melted liquid plastic waste will be filtered at the filter plate, and the intercepted particulate impurities will accumulate on the filter plate. After the filtration is completed, the opening and closing electric cylinder drives the plate shaft to drive the movable plate to move upward to open the channel. At this time, the propulsion electric cylinder drives the push rod to push the arc plate to clear the particulate impurities accumulated on the filter plate and push them out of the hot melt bin from the opening of the channel. When the arc plate fits with the groove, the particulate impurities are pushed into the space between the spiral blades of the stacked screw shaft. The compression motor drives the rotating shaft to drive the stacked screw shaft to rotate, so as to compress and push the particulate impurities, and finally they fall into the collection box for collection. Through the above structure, the device realizes the function of processing the filtered impurities.
[0017] 2. The present invention is provided with a purification component. When the plastic waste is heated and melted in the hot melt bin, harmful organic waste gas will be generated. The waste gas will enter the air box through the air pipe. The fan starts to exhaust outward. The waste gas is adsorbed and purified by the adsorption plate, and the purified gas will be discharged through the exhaust of the fan. Through the above structure, the integrated waste gas treatment effect of the device is realized.
[0018] 3. The present invention is provided with a heat exchange component. During the filtration process of the liquid plastic waste, the plastic fluid will flow in the pipeline of the thin pipe. The heating oil is injected into the interior of the heat exchange bin from the liquid inlet pipe and flows out from the liquid discharge pipe. The small pipeline of the thin pipe is used to further increase the heat exchange area of the liquid plastic, and the heating oil is used to heat it, so as to keep it in a high-temperature flowing state and prevent it from quickly solidifying and affecting its transmission effect. The filtered liquid plastic is discharged from the liquid discharge port, and the fixing frame can be externally connected to other devices to further process the liquid plastic. Brief Description of the Drawings
[0019] Figure 1 It is a schematic diagram of the overall structure of the present invention.
[0020] Figure 2 It is a schematic diagram of the structure of the hot melt component of the present invention.
[0021] Figure 3 It is a schematic diagram of the structure at the arc plate of the present invention.
[0022] Figure 4 It is a schematic diagram of the structure of the compression component of the present invention.
[0023] Figure 5 It is a schematic sectional view of the structure at the compression component of the present invention.
[0024] Figure 6 It is a schematic diagram of the structure of the purification component of the present invention.
[0025] Figure 7 This is a schematic structural diagram of the heat exchange component of the present invention.
[0026] The reference numerals are: 1, hot melt component; 101, hot melt bin; 102, bottom plate; 103, filter plate; 104, heating pipe; 105, movable groove; 106, channel; 107, movable plate; 108, plate shaft; 109, opening and closing electric cylinder; 110, upper plate; 111, feeding pipe; 112, connection hole; 113, propulsion electric cylinder; 114, push rod; 115, arc plate; 2, compression component; 201, arc cylinder; 202, semi-arc piece; 203, embedding groove; 204, stacked screw shaft; 205, rotating shaft; 206, fixing plate; 207, compression motor; 208, collection box; 3, purification component; 301, air box; 302, fan; 303, adsorption plate; 304, box plate; 305, air pipe; 4, heat exchange component; 401, thin pipe; 402, liquid discharge plate; 403, external connection plate; 404, heat exchange bin; 405, liquid inlet pipe; 406, liquid discharge pipe; 407, connecting piece; 408, liquid discharge port; 409, connecting frame; 410, fixing frame. Detailed implementation manners
[0027] Next, the technical solutions in the present invention will be clearly and completely described in conjunction with the drawings in the present invention. In addition, the forms of the various structures described in the following embodiments are merely examples, and a plastic particle waste hot melt treatment device related to the present invention is not limited to the various structures described in the following embodiments. All other embodiments obtained without creative work by those of ordinary skill in the art belong to the scope of protection of the present invention.
[0028] Referring to Figure 1 , the present invention provides a plastic particle waste hot melt treatment device, including a hot melt component 1. A compression component 2 is fixedly installed on one side of the hot melt component 1, a purification component 3 is fixedly installed on the other side of the hot melt component 1, and a heat exchange component 4 is fixedly installed at the bottom end of the hot melt component 1;
[0029] In this embodiment, the hot melt component 1 is used to heat and melt plastic particle waste, the compression component 2 is used to process the impurity particles accumulated at the bottom of the hot melt component 1 during the filtration process, the purification component 3 is used to purify the organic waste gas generated during the heating process of the hot melt component 1, and the heat exchange component 4 is used to perform secondary heating on the refined and shunted liquid plastic waste during the filtration process, so as to prevent it from solidifying after filtration and affecting its transportation and flow effect. The specific structures and working principles of the above components will be described in detail later.
[0030] Referring to Figure 2 and Figure 3, the hot-melt assembly 1 includes a hot-melt bin 101. A bottom plate 102 is fixedly installed at the bottom end of the hot-melt bin 101. A filter plate 103 is fixedly installed on the bottom plate 102. A heating pipe 104 is fixedly installed on the inner wall of the bottom end of the hot-melt bin 101. An activity slot 105 is opened on the inner wall of the hot-melt bin 101. A channel 106 is opened at the bottom of the activity slot 105. An activity plate 107 is movably sleeved in the activity slot 105. An upper end of the activity plate 107 is fixedly connected to a plate shaft 108. The plate shaft 108 is located in the activity slot 105. An upper end of the shaft body of the plate shaft 108 is fixedly connected to an opening and closing electric cylinder 109. When the activity plate 107 is at the lowest end, the channel 106 is closed. An upper plate 110 is fixedly installed at the upper end of the hot-melt bin 101. An inlet pipe 111 is fixedly connected to the upper end of the upper plate 110. A connection hole 112 is opened on the upper plate 110. The opening and closing electric cylinder 109 is fixedly installed on the upper surface of the upper plate 110. A propulsion electric cylinder 113 is fixedly installed at the outer side surface of the hot-melt bin 101. A driving end of the propulsion electric cylinder 113 is fixedly connected to a push rod 114. A shaft body end of the push rod 114 is fixedly connected to an arc plate 115. The arc plate 115 is aligned with the channel 106 and has a length and width that are mutually adapted;
[0031] In this embodiment, plastic waste is input into the hot-melt bin 101 from the inlet pipe 111. Under the heating action of the heating pipe 104, the plastic waste is heated and melted, thereby facilitating subsequent processing work. Since this process is a conventional technical means known to those skilled in the art, the specific structure and working principle of the above process are not described in detail in this embodiment.
[0032] Refer to Figure 4 and Figure 5 , the compression assembly 2 includes an arc cylinder 201. The arc cylinder 201 is fixedly connected to the side end of the bottom plate 102. The arc cylinder 201 is fixedly connected to a semi-arc member 202. An embedding groove 203 is opened on the semi-arc member 202. The embedding groove 203 is mutually adapted to the arc plate 115. After the arc plate 115 fits into the embedding groove 203, it forms a cylinder member with the arc cylinder 201 and the semi-arc member 202. A stacked screw shaft 204 is movably sleeved inside the cylinder member formed by the arc cylinder 201. A rotating shaft 205 is fixedly sleeved at the center of the stacked screw shaft 204. A fixed plate 206 is fixedly installed at the front end of the arc cylinder 201. A compression motor 207 is fixedly installed on the fixed plate 206. A driving end of the compression motor 207 is fixedly connected to the shaft body of the rotating shaft 205. A collection box 208 is provided at the rear end of the arc cylinder 201. The collection box 208 is fixedly installed at the outer side surface of the hot-melt bin 101;
[0033] In this embodiment, the melted liquid plastic waste is filtered at the filter plate 103, and the intercepted particulate impurities will accumulate on the filter plate 103. After the filtration is completed, the opening and closing electric cylinder 109 drives the plate shaft 108 to drive the movable plate 107 to move upward to open the channel 106. At this time, the propulsion electric cylinder 113 drives the push rod 114 to push the arc plate 115 to clear and push the particulate impurities accumulated on the filter plate 103, and push them out of the hot melt bin 101 from the opening of the channel 106. When the arc plate 115 fits into the groove 203, the particulate impurities are pushed between the spiral blades of the stacked screw shaft 204. The compression motor 207 drives the rotating shaft 205 to drive the stacked screw shaft 204 to rotate, so as to compress and push the particulate impurities, and finally drop into the collection box 208 for collection. Through the above structure, the device realizes the function of processing the filtered impurities.
[0034] Refer to Figure 6 , the purification component 3 includes an air box 301, a fan 302 is fixedly installed on the outer side of the air box 301, an adsorption plate 303 is fixedly installed inside the air box 301, the installation height of the adsorption plate 303 is higher than that of the fan 302, a box plate 304 is fixedly installed at the upper end of the air box 301, a trachea 305 is fixedly connected to the box plate 304, and the pipe end of the trachea 305 is fixedly connected to the connection hole 112;
[0035] In this embodiment, when the plastic waste is heated and melted in the hot melt bin 101, harmful organic waste gas will be generated. The waste gas will enter the air box 301 through the trachea 305. The fan 302 starts to exhaust outward. The waste gas is adsorbed and purified by the adsorption plate 303, and the purified gas will be discharged through the exhaust of the fan 302. Through the above structure, the integrated waste gas treatment effect of the device is realized.
[0036] Refer to Figure 7 , the heat exchange component 4 includes a thin tube 401. The number of the thin tubes 401 is the same as the number of the filter holes on the filter plate 103. The thin tubes 401 are sequentially connected to the filter holes on the filter plate 103. A liquid discharge plate 402 is fixedly installed at the bottom end of the thin tube 401, an external connection plate 403 is fixedly installed at the outer end of the liquid discharge plate 402, a heat exchange bin 404 is fixedly installed between the bottom plate 102 and the external connection plate 403, a liquid inlet pipe 405 is fixedly connected to the lower side of one side of the heat exchange bin 404, a liquid discharge pipe 406 is fixedly connected to the upper side of the other side of the heat exchange bin 404, a connecting piece 407 is fixedly connected to the bottom of the external connection plate 403, a liquid discharge port 408 is fixedly installed at the bottom end of the connecting piece 407, and connecting frames 409 are fixedly installed at both ends of the connecting piece 407. The bottom end of the connecting frame 409 is fixedly connected to a fixing frame 410;
[0037] In this embodiment, during the filtration process of liquid plastic waste, the plastic fluid will flow in the pipeline of the thin tube 401. The heating oil is injected into the interior of the heat exchange chamber 404 from the liquid inlet pipe 405 and flows out from the liquid discharge pipe 406. The small pipeline of the thin tube 401 is used to further increase the heat exchange area of the liquid plastic, and the heating oil is used to heat it, so as to keep it in a high-temperature flowing state and prevent it from quickly solidifying and affecting its transmission effect. The filtered liquid plastic is discharged from the liquid discharge port 408, and the fixing frame 410 can be externally connected to other devices for further processing of the liquid plastic.
[0038] The working principle of the present invention: Plastic waste is put into the hot melt chamber 101 from the feed pipe 111, and the plastic waste is heated and melted under the heating action of the heating pipe 104. The melted liquid plastic waste will be filtered at the filter plate 103, and the intercepted particulate impurities will accumulate on the filter plate 103. When the filtration is completed, the opening and closing electric cylinder 109 drives the plate shaft 108 to drive the movable plate 107 to move upward to open the channel 106. At this time, the propulsion electric cylinder 113 drives the push rod 114 to push the arc plate 115 to clear and push the particulate impurities accumulated on the filter plate 103, and push them out of the hot melt chamber 101 from the opening of the channel 106. When the arc plate 115 fits with the groove 203, the particulate impurities are pushed into the space between the spiral blades of the stacked screw shaft 204. The compression motor 207 drives the rotating shaft 205 to drive the stacked screw shaft 204 to rotate, so as to compress and push the particulate impurities, and finally fall into the collection box 208 for collection. Through the above structure, the device realizes the function of processing the filtered impurities. When the plastic waste is heated and melted in the hot melt chamber 101, harmful organic waste gas will be generated. The waste gas will enter the gas box 301 through the air pipe 305. The fan 302 starts to exhaust outward. The waste gas is adsorbed and purified by the adsorption plate 303, and the purified gas will be discharged through the exhaust of the fan 302. Through the above structure, the device realizes the integrated waste gas treatment effect. During the filtration process of liquid plastic waste, the plastic fluid will flow in the pipeline of the thin tube 401. The heating oil is injected into the interior of the heat exchange chamber 404 from the liquid inlet pipe 405 and flows out from the liquid discharge pipe 406. The small pipeline of the thin tube 401 is used to further increase the heat exchange area of the liquid plastic, and the heating oil is used to heat it, so as to keep it in a high-temperature flowing state and prevent it from quickly solidifying and affecting its transmission effect. The filtered liquid plastic is discharged from the liquid discharge port 408, and the fixing frame 410 can be externally connected to other devices for further processing of the liquid plastic.
[0039] The following points should be noted: First, in the description of this application, it should be noted that unless otherwise specified and defined, the terms "installed", "connected", and "coupled" should be understood in a broad sense, which can be a mechanical connection or an electrical connection, or the communication inside two components, and can be directly connected. The terms "upper", "lower", "left", "right", etc. are only used to represent the relative positional relationship. When the absolute position of the object being described changes, the relative positional relationship may change;
[0040] Second, in the drawings of the disclosed embodiments of the present invention, only the structures related to the disclosed embodiments are involved. For other structures, reference can be made to the general design. Without conflict, the same embodiment and different embodiments of the present invention can be combined with each other;
[0041] Finally, the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.
Claims
1. A device for hot-melting waste plastic particles, characterized in that: It comprises a hot melt component (1), a compression component (2) is fixedly mounted on one side of the hot melt component (1), a purification component (3) is fixedly mounted on the other side of the hot melt component (1), and a heat exchange component (4) is fixedly mounted on the bottom end of the hot melt component (1); The hot melt assembly (1) comprises a hot melt chamber (101), a bottom plate (102) is fixedly mounted at the bottom end of the hot melt chamber (101), a filter plate (103) is fixedly mounted on the bottom plate (102), a heating tube (104) is fixedly mounted on the inner wall of the bottom end of the hot melt chamber (101), a movable groove (105) is provided on the inner wall of the hot melt chamber (101), a channel (106) is provided at the bottom of the movable groove (105), a movable plate (107) is movably sleeved in the movable groove (105), a plate shaft (108) is fixedly connected to the upper end of the movable plate (107), the plate shaft (108) is located in the movable groove (105), and an opening and closing electric cylinder (107) is fixedly connected to the upper end of the shaft body of the plate shaft (108). 9), when the movable plate (107) is located at the lowest end, the channel (106) is closed, an upper plate (110) is fixedly installed on the upper end of the hot melt bin (101), and a feed pipe (111) is fixedly connected to the upper end of the upper plate (110), and a connection hole (112) is opened on the upper plate (110), the opening and closing electric cylinder (109) is fixedly installed on the upper surface of the upper plate (110), and a propulsion electric cylinder (113) is fixedly installed on the outer side surface of the hot melt bin (101), and a push rod (114) is fixedly connected to the driving end of the propulsion electric cylinder (113), and an arc plate (115) is fixedly connected to the end of the shaft of the push rod (114), and the arc plate (115) and the channel (106) are aligned with each other and the length and width are adapted to each other.
2. The device for hot-melting waste plastic particles according to claim 1, characterized in that: The compression assembly (2) comprises an arc tube (201), wherein the arc tube (201) is fixedly connected to the side end of the bottom plate (102), and the arc tube (201) is fixedly connected to a semi-arc member (202), wherein an embedding groove (203) is provided on the semi-arc member (202), and the embedding groove (203) and the arc plate (115) are mutually adapted, and the arc plate (115) and the embedding groove (203) are matched to form a cylinder member together with the arc tube (201) and the semi-arc member (202).
3. The device for hot-melting waste plastic particles according to claim 2, characterized in that: The cylinder member formed by the arc cylinder (201) has a stacked screw shaft (204) movably sleeved inside, and a rotating shaft (205) is fixedly sleeved at the center of the stacked screw shaft (204). A fixed plate (206) is fixedly installed at the front end of the arc cylinder (201), and a compression motor (207) is fixedly installed on the fixed plate (206). The driving end of the compression motor (207) is fixedly connected to the shaft body of the rotating shaft (205). A collection box (208) is provided at the rear end of the arc cylinder (201), and the collection box (208) is fixedly installed on the outer side of the hot melt bin (101).
4. The device for hot-melting waste plastic particles according to claim 1, characterized in that: The purification component (3) comprises an air box (301), a fan (302) is fixedly mounted on the outer side of the air box (301), an adsorption plate (303) is fixedly mounted inside the air box (301), the installation height of the adsorption plate (303) is higher than that of the fan (302), a box plate (304) is fixedly mounted on the upper end of the air box (301), an air pipe (305) is fixedly connected to the box plate (304), and the pipe end of the air pipe (305) is fixedly connected to the connecting hole (112).
5. The device for hot-melting waste plastic particles according to claim 1, characterized in that: The heat exchange component (4) comprises a capillary tube (401), the number of the capillary tubes (401) being consistent with the number of filter holes on the filter plate (103), the capillary tubes (401) being sequentially interconnected with the filter holes on the filter plate (103), a liquid discharge plate (402) being fixedly mounted at the bottom end of the capillary tube (401), and an external plate (403) being fixedly mounted at the outer end of the liquid discharge plate (402).
6. The device for hot-melting waste plastic particles according to claim 5, characterized in that: A heat exchange chamber (404) is fixedly installed between the bottom plate (102) and the external plate (403); a liquid inlet pipe (405) is fixedly connected to the lower side of one side of the heat exchange chamber (404); a liquid discharge pipe (406) is fixedly connected to the upper side of the other side of the heat exchange chamber (404); a connecting piece (407) is fixedly connected to the bottom of the external plate (403); a liquid discharge port (408) is fixedly installed at the bottom end of the connecting piece (407); connecting frames (409) are fixedly installed at both ends of the connecting piece (407); and a fixing frame (410) is fixedly connected to the bottom end of the connecting frame (409).