A mold cavity pressure detection device

Abstract

The application provides a mold cavity pressure detection device, and belongs to the technical field of molds. The device solves the problem of low detection precision of the existing injection mold cavity pressure. The mold comprises an upper mold and a lower mold, and the upper mold and the lower mold have a mold cavity therebetween. The detection device comprises a detection groove in the lower mold and communicating with the mold cavity, a sensing sheet fixedly sealed at the communication position of the detection groove and the mold cavity and capable of generating a certain deformation, a sealing disc slidingly arranged in the detection groove and sealingly attached to the groove wall, a filling liquid between the sensing sheet and the sealing disc, a detection rod fixedly connected to the center of the bottom of the sealing disc, and a strain sheet installed in the detection groove. The detection rod abuts against the strain sheet, and a first elastic member is arranged on the detection rod. The two ends of the first elastic member act on the sealing disc and the lower mold, respectively. The mold cavity pressure detection device has the advantage of improving the detection precision of the mold cavity pressure.

Description

Technical Field

[0001] This invention belongs to the field of mold technology and relates to a device for detecting the pressure of a mold cavity. Background Technology

[0002] Injection molds are tools used to produce plastic products, giving them a complete structure and precise dimensions. Specifically, they involve injecting molten plastic into a mold cavity under high pressure using an injection molding machine, where it cools and solidifies to obtain the molded product.

[0003] In the production and processing of injection molds, in order to improve the processing quality of the mold, it is necessary to detect the pressure of the molten plastic in the mold cavity. Existing detection structures, such as the ejector pin structure of injection molds disclosed in Chinese patent literature [Application No.: 201520780902.1; Authorization Announcement No.: CN205021931U], include an ejector pin, a metal frame is provided below one end of the ejector pin, a supporting diaphragm frame is provided on the inner bottom surface of the metal frame, and a resistance strain gauge is fixed on the inner top surface of the supporting diaphragm frame, which can output a voltage signal to the outside through a signal amplification circuit, and the voltage signal value changes due to its mechanical deformation. One end of the ejector pin penetrates into the metal frame and abuts against the outer top surface of the supporting diaphragm frame.

[0004] In this type of ejector pin structure, when the injection mold is working on the injection molding machine, the molten plastic in the mold cavity exerts pressure on the ejector pin. The ejector pin withstands this pressure and transmits it to the resistance strain gauge, which then outputs a voltage signal through the signal amplification circuit. However, in this type of ejector pin structure, the ejector pin's function is to eject the product, therefore the ejector pin diameter is relatively small, meaning the contact area between the ejector pin and the molten plastic in the mold cavity is relatively small, resulting in a small sensing area and reduced detection accuracy. Furthermore, the ejector pin is a rigid rod, passing through the guide hole in the mold, and there is a certain amount of friction between the ejector pin and the guide hole wall, which also reduces detection accuracy. Additionally, due to the relatively long ejector pin, there is a risk of it tilting and getting stuck in the mold during movement, further reducing detection accuracy. Summary of the Invention

[0005] The purpose of this invention is to address the aforementioned problems in the prior art by proposing a device for detecting pressure in a mold cavity, thereby solving the technical problem of how to improve the detection accuracy of pressure within the mold cavity.

[0006] The objective of this invention can be achieved through the following technical solution: a device for detecting the pressure of a mold cavity, the mold including an upper mold and a lower mold, wherein a cavity is provided between the upper mold and the lower mold, characterized in that the detection device includes a detection groove in the lower mold communicating with the cavity, a sensing plate that is sealed and fixed at the communication point between the detection groove and the cavity and can generate a certain deformation, a sealing plate that is slidably inserted in the detection groove and sealed against the groove wall, a filling liquid located between the sensing plate and the sealing plate, a detection rod fixed at the center of the bottom of the sealing plate, and a strain gauge installed in the detection groove, wherein the detection rod abuts against the strain gauge, and a first elastic element is sleeved on the detection rod, the two ends of the first elastic element acting on the sealing plate and the lower mold respectively.

[0007] The strain gauge is a resistance strain gauge, a current technology. Its working principle is based on the strain effect, where the resistance of a conductor or semiconductor material changes accordingly when it undergoes mechanical deformation under external force. After molten plastic is injected into the mold cavity, a certain pressure is created. The molten plastic pushes the sensing element, causing it to deform. This deformation pushes the filling liquid to flow, which in turn moves the sealing disc. The sealing disc moves the detection rod, which transmits the pressure to the strain gauge, causing it to deform mechanically. The strain gauge then receives this pressure and sends a signal, allowing the operator to obtain the pressure within the mold cavity. This non-contact, dynamic transmission of deformation from the sensing element to the strain gauge through the filling liquid negligibles the influence of friction and eliminates the risk of jamming. This ensures accurate transmission of deformation from the sensing element to the strain gauge, improving the detection accuracy of the pressure within the mold cavity. While the sensing element can withstand high temperatures and pressures, the strain gauge is susceptible to damage from high temperatures. The sealing disc acts as a seal, preventing filling liquid leakage. The filling liquid also facilitates cooling, preventing heat transfer to the sealing disc and strain gauge, thus reducing their damage and improving detection accuracy. Since pressure is transmitted through the filling liquid, the inner diameter of the detection groove can be made relatively large, increasing the sensing area of ​​the sensing element and thus improving the detection accuracy of the pressure inside the mold cavity. The first elastic element acts as an elastic reset element, keeping the detection rod in the set position while avoiding adverse effects caused by changes in the volume of the filling liquid, ensuring detection accuracy.

[0008] In the aforementioned mold cavity pressure detection device, the lower mold includes an inner mold located inside and used to form the mold cavity. The detection groove is located in the inner mold and penetrates through the inner mold. The inner mold is an independent component located inside, which allows the detection groove to be made shorter, reducing interference and improving the detection accuracy of the pressure inside the mold cavity. Moreover, the detection groove penetrating through the inner mold facilitates the installation of the sensing element, filling fluid, and strain gauge.

[0009] In the aforementioned mold cavity pressure detection device, the sensing element is made of a thin metal sheet. The sensing element can bulge and deform towards the sealing disc, and the side of the sensing element facing the mold cavity is part of the mold cavity wall. The sensing element is a metal sheet that senses pressure deformation but cannot detect pressure. The sensing element can be fixed to the inner mold through processes such as welding and grinding. The sensing element will deform under force, but the deformation is very small and will not affect the product quality.

[0010] In the aforementioned mold cavity pressure detection device, a guide plate is fixedly connected in the detection groove. The guide plate is located between the sealing plate and the strain gauge. The detection rod passes through the guide plate, and the two ends of the first elastic element act on the sealing plate and the guide plate, respectively. The guide plate serves as a guide, causing the detection rod to move in a set direction, preventing the detection rod from getting stuck and improving the detection accuracy of the mold cavity pressure. The guide plate can also be replaced by an annular guide portion protruding inward from the detection groove wall.

[0011] In the aforementioned mold cavity pressure detection device, a limiting plate is fixedly connected to the wall of the detection groove. The limiting plate is located between the guide plate and the strain gauge. The limiting plate has a limiting hole, through which the detection rod passes, with a clearance fit between the detection rod and the hole wall. The detection rod has an outwardly protruding abutment. After the detection rod moves a predetermined distance toward the strain gauge, the abutment abuts against the limiting plate. The limiting plate serves two purposes: first, it guides the detection rod, preventing it from deflecting or getting stuck during movement, thus improving the accuracy of mold cavity pressure detection; second, it limits the movement of the detection rod, preventing excessive travel and damage to the strain gauge.

[0012] In the aforementioned mold cavity pressure detection device, a limiting ring is fixedly connected to the wall of the detection groove. The limiting ring is located between the sensing plate and the sealing disc, and is positioned close to the sealing disc. After the sealing disc moves a predetermined distance toward the sensing plate, it abuts against the limiting ring. The limiting ring limits the movement of the sealing disc, preventing excessive travel and damage to the sensing plate.

[0013] In the aforementioned mold cavity pressure detection device, the top of the lower mold has several blind holes, and a pressure sensor is fixedly connected to the bottom of each blind hole. A counting rod and a second elastic element pass through each blind hole. The two ends of the second elastic element act on the counting rod and the hole wall of the blind hole, respectively. Under the action of the elastic force of the second elastic element, the top of the counting rod extends out of the blind hole. When the upper and lower molds are closed, the upper mold causes the counting rod to move downward against the elastic force of the second elastic element and contact the pressure sensor. The second elastic element provides elastic force, causing the counting rod to move upward without contacting the pressure sensor when the mold is opened, and to move downward to contact the pressure sensor when the mold is closed. The pressure sensor senses two different states, and can calculate the number of times the mold is opened and closed, and send out the signal.

[0014] In the aforementioned mold cavity pressure detection device, both the first elastic element and the second elastic element are cylindrical springs or conical springs.

[0015] In the aforementioned mold cavity pressure detection device, the lower mold further includes an outer mold and a bottom mold. The outer mold is detachably fixed to the bottom mold. The bottom of the outer mold has a protruding anti-disassembly post, and the top of the bottom mold has a recessed anti-disassembly hole. A trigger is installed in the anti-disassembly hole. When the outer mold and the bottom mold are fixed together, the anti-disassembly post extends into the anti-disassembly hole and connects to the trigger. When the outer mold and the bottom mold are separated, the anti-disassembly post leaves the anti-disassembly hole and disengages from the trigger. The outer mold and the bottom mold are not allowed to be disassembled by the operator. The anti-disassembly post and the trigger work together to provide an alarm, allowing the manufacturing company to determine whether the outer mold and the bottom mold have been disassembled based on the signals emitted by the anti-disassembly post and the trigger.

[0016] In the aforementioned mold cavity pressure detection device, the trigger includes a connecting block protruding and fixed to the inner wall of the anti-disassembly hole. A trigger rod is hinged to the connecting block. A torsion spring is provided between the connecting block and the trigger rod, with both ends of the torsion spring acting on the connecting block and the trigger rod respectively. When the outer mold and the bottom mold are fixedly connected, the trigger rod abuts against the anti-disassembly post under the torsion force of the torsion spring. When the outer mold and the bottom mold are separated, the anti-disassembly post overcomes the torsion force of the torsion spring and disengages from the trigger rod. This structure allows for flexible contact between the trigger rod and the anti-disassembly post, ensuring that the trigger is not damaged after the outer mold and the bottom mold are disassembled, and allowing for reuse.

[0017] In the aforementioned mold cavity pressure detection device, the detection device includes a central control module and a signal transmission module. The central control module is embedded between the outer mold and the bottom mold, and the signal transmission module is installed at the bottom of the bottom mold. The central control module is electrically connected to the strain gauge, the trigger, and the signal transmission module. The central control module receives electrical signals from the strain gauge, the pressure sensor, and the trigger, and can transmit them to the operator or the manufacturing company through the signal transmission module. Since the central control module is located between the outer mold and the bottom mold, operators are generally not allowed to disassemble the outer mold and the bottom mold themselves.

[0018] Compared with the prior art, the mold cavity pressure detection device provided by the present invention has the following advantages:

[0019] 1. This detection device transmits the deformation of the sensing element to the strain gauge through the filling liquid. It is a non-contact dynamic transmission, so the influence of friction is negligible and there is no problem of jamming. This allows the deformation of the sensing element to be accurately transmitted to the strain gauge, improving the detection accuracy of the pressure inside the mold cavity.

[0020] 2. This detection device has multiple detection slots, which are distributed in different positions to detect the pressure in different parts of the mold cavity, thereby improving the detection accuracy of the pressure inside the mold cavity. At the same time, the inner diameter of the detection slots can be made relatively large to increase the sensing area of ​​the sensing element, thereby improving the detection accuracy of the pressure inside the mold cavity.

[0021] 3. This testing device can also detect the number of times the mold is opened and closed, as well as whether the outer mold and bottom mold have been disassembled without authorization, making it versatile in function. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the overall structure of the device for detecting the pressure in the mold cavity.

[0023] Figure 2 This is the detection device Figure 1 Enlarged view of area A.

[0024] Figure 3 This is the detection device Figure 1 Enlarged view of area B.

[0025] Figure 4 This is the detection device Figure 1 Enlarged view of region C.

[0026] Figure 5 This is the detection device Figure 4 Enlarged view of region D.

[0027] In the diagram, 1. Upper mold; 2. Lower mold; 201. Inner mold; 202. Blind hole; 203. Outer mold; 204. Bottom mold; 3. Mold cavity; 4. Detection groove; 5. Sensor; 6. Sealing plate; 7. Filling liquid; 8. Detection rod; 81. Abutment part; 9. Guide plate; 10. Strain gauge; 11. First elastic element; 12. Limiting plate; 121. Limiting hole; 13. Limiting ring; 14. Pressure sensor; 15. Counting rod; 16. Second elastic element; 17. Anti-tampering post; 18. Anti-tampering hole; 19. Trigger; 191. Connecting block; 192. Trigger rod; 193. Torsion spring; 20. Central control module; 21. Signal transmission module. Detailed Implementation

[0028] The following are specific embodiments of the present invention, which are described in conjunction with the accompanying drawings. However, the present invention is not limited to these embodiments.

[0029] like Figure 1 As shown, this mold includes an upper mold 1, a lower mold 2, and a mold cavity 3 pressure detection device. There is a mold cavity 3 between the upper mold 1 and the lower mold 2. The detection device includes a detection groove 4, a sensing plate 5, a sealing plate 6, a filling liquid 7, a detection rod 8, a guide plate 9, a strain gauge 10, a first elastic element 11, a central control module 20, and a signal transmission module 21.

[0030] The lower mold 2 includes an inner mold 201, an outer mold 203, and a bottom mold 204. The inner mold 201 is located within the outer mold 203 and forms the mold cavity 3. The outer mold 203 is detachably fixed to the bottom mold 204. In this embodiment, there are five detection slots 4. The detection slots 4 penetrate the inner mold 201 and are connected to the mold cavity 3. That is, this detection device has five detection positions. When the pressure fluctuations detected at the five detection positions are within the set range, it indicates that the pressure inside the mold cavity is normal. When the pressure fluctuations detected at the five detection positions are outside the set range, it indicates that the pressure inside the mold cavity is abnormal and requires maintenance. Multiple detection positions allow for detection of different areas, increasing the detection range. In actual production, the number of detection slots 4 can be three or seven. The central control module 20 is embedded between the outer mold 203 and the bottom mold 204, and the signal transmission module 21 is installed at the bottom of the bottom mold 204.

[0031] like Figure 2 As shown, the sensing element 5 is made of a thin metal sheet. It is sealed and fixed to the connection between the detection groove 4 and the mold cavity 3 through welding and grinding processes. The sensing element 5 can deform and bulge towards the sealing disc 6, and the side of the sensing element 5 facing the mold cavity 3 is part of the cavity wall of the mold cavity 3. The sealing disc 6 slides through the detection groove 4 and is sealed and fitted to the groove wall of the detection groove 4. The filling liquid 7, which is water, is located between the sensing element 5 and the sealing disc 6. The detection rod 8 is fixedly connected to the center of the bottom of the sealing disk 6. The guide disk 9, strain gauge 10, and limiting disk 12 are all fixedly connected in the detection groove 4. The guide disk 9 is located between the sealing disk 6 and the limiting disk 12, and the limiting disk 12 is located between the guide disk 9 and the strain gauge 10. The limiting disk 12 has a limiting hole 121. The detection rod 8 passes through the guide disk 9 and the limiting hole 121 and contacts the strain gauge 10. The detection rod 8 and the hole wall of the limiting hole 121 are in clearance fit. Both the guide disk 9 and the limiting hole 121 guide the detection rod 8. The detection rod 8 has an outwardly protruding abutment part 81. After the detection rod 8 moves a set distance toward the strain gauge 10, the abutment part 81 abuts against the limiting disk 12. A limiting ring 13 is fixedly connected to the groove wall of the detection groove 4. The limiting ring 13 is located between the sensing element 5 and the sealing disk 6 and is close to the sealing disk 6. After the sealing disk 6 moves a set distance toward the sensing element 5, it abuts against the limiting ring 13. The detection rod 8 is fitted with a first elastic element 11, and the two ends of the first elastic element 11 act on the sealing disc 6 and the guide disc 9 respectively.

[0032] In this embodiment, the top of the lower mold 2 has two blind holes 202. In actual production, the number of blind holes 202 can be one or four. Figure 3As shown, a pressure sensor 14 is fixedly connected to the bottom of the blind hole 202. A counting rod 15 and a second elastic element 16 pass through the blind hole 202. The two ends of the second elastic element 16 act on the counting rod 15 and the hole wall of the blind hole 202, respectively. Under the action of the elastic force of the second elastic element 16, the top of the counting rod 15 extends out of the blind hole 202. When the upper mold 1 and the lower mold 2 are closed, the upper mold 1 causes the counting rod 15 to move downward against the elastic force of the second elastic element 16 and contact the pressure sensor 14. In this embodiment, the first elastic element 11 and the second elastic element 16 are both cylindrical springs. In actual production, the first elastic element 11 and the second elastic element 16 can both be conical springs.

[0033] like Figure 4 As shown, the bottom of the outer mold 203 has a protruding anti-tamper post 17, and the top of the bottom mold 204 has a recessed anti-tamper hole 18. A trigger 19 is installed in the anti-tamper hole 18. Figure 5 As shown, the trigger 19 includes a connecting block 191 protruding and fixed to the inner wall of the anti-tamper hole 18. A trigger rod 192 is hinged to the connecting block 191. A torsion spring 193 is provided between the connecting block 191 and the trigger rod 192, and the two ends of the torsion spring 193 act on the connecting block 191 and the trigger rod 192 respectively. When the outer mold 203 and the bottom mold 204 are fixed together, the anti-tamper post 17 extends into the anti-tamper hole 18. The trigger rod 192 abuts against the anti-tamper post 17 under the action of the torsion of the torsion spring 193. When the outer mold 203 and the bottom mold 204 are separated, the anti-tamper post 17 leaves the anti-tamper hole 18 and the anti-tamper post 17 overcomes the torsion of the torsion spring 193 and separates from the trigger rod 192.

[0034] The central control module 20 is electrically connected to the strain gauge 10, pressure sensor 14, trigger 19, and signal transmission module 21. During measurement, molten plastic is injected into the mold cavity 3, creating a certain pressure within it. The molten plastic pushes the sensing element 5, causing it to bulge and deform towards the sealing disk 6. The sensing element 5 then pushes the filling liquid 7 to flow, thereby moving the sealing disk 6. This causes the detection rod 8 to transmit the pressure to the strain gauge 10, which receives the pressure and transmits it to the central control module 20 via an electrical signal.

[0035] The specific embodiments described herein are merely illustrative of the spirit of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to substitute them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

[0036] Although this document frequently uses terms such as upper mold 1, lower mold 2, inner mold 201, blind hole 202, outer mold 203, bottom mold 204, mold cavity 3, detection groove 4, sensing plate 5, sealing plate 6, filling liquid 7, detection rod 8, abutment part 81, guide plate 9, strain gauge 10, first elastic element 11, limiting plate 12, limiting hole 121, limiting ring 13, pressure sensor 14, counting rod 15, second elastic element 16, anti-tamper post 17, anti-tamper hole 18, trigger 19, connecting block 191, trigger rod 192, torsion spring 193, central control module 20, and signal transmission module 21, the possibility of using other terms is not excluded. The use of these terms is merely for the convenience of describing and explaining the essence of the invention; interpreting them as any additional limitation would contradict the spirit of the invention.

Claims

1. A device for detecting the pressure of a mold cavity, the mold comprising an upper mold (1) and a lower mold (2), wherein a cavity (3) is provided between the upper mold (1) and the lower mold (2), characterized in that, The detection device includes a detection groove (4) in the lower mold (2) that is connected to the mold cavity (3), a sensing plate (5) that is sealed and fixed at the connection between the detection groove (4) and the mold cavity (3) and can generate a certain deformation, a sealing plate (6) that is slidably inserted in the detection groove (4) and sealed and fitted with the groove wall of the detection groove (4), a filling liquid (7) located between the sensing plate (5) and the sealing plate (6), a detection rod (8) fixed at the bottom center of the sealing plate (6), and a strain gauge (10) installed in the detection groove (4). The detection rod (8) abuts against the strain gauge (10). The detection rod (8) is covered with a first elastic element (11). The two ends of the first elastic element (11) act on the sealing plate (6) and the lower mold (2) respectively.

2. The device for detecting mold cavity pressure according to claim 1, characterized in that, The lower mold (2) includes an inner mold (201) located inside and used to form a mold cavity (3), and the detection groove (4) is located in the inner mold (201) and penetrates the inner mold (201).

3. The device for detecting mold cavity pressure according to claim 1, characterized in that, The sensing sheet (5) is made of a thin metal sheet. The sensing sheet (5) can bulge and deform toward the sealing disc (6). The side of the sensing sheet (5) facing the mold cavity (3) is part of the cavity wall of the mold cavity (3).

4. A device for detecting mold cavity pressure according to claim 1, 2, or 3, characterized in that, A guide plate (9) is fixed in the detection groove (4). The guide plate (9) is located between the sealing plate (6) and the strain gauge (10). The detection rod (8) passes through the guide plate (9). The two ends of the first elastic element (11) act on the sealing plate (6) and the guide plate (9) respectively.

5. The mold cavity pressure detection device according to claim 4, characterized in that, A limiting disk (12) is fixedly connected to the wall of the detection groove (4). The limiting disk (12) is located between the guide disk (9) and the strain gauge (10). The limiting disk (12) has a limiting hole (121). The detection rod (8) passes through the limiting hole (121) and the detection rod (8) and the hole wall of the limiting hole (121) are in clearance fit. The detection rod (8) has an outwardly protruding abutment (81). After the detection rod (8) moves a set distance toward the strain gauge (10), the abutment (81) abuts against the limiting disk (12).

6. A device for detecting mold cavity pressure according to claim 1, 2, or 3, characterized in that, A limiting ring (13) is fixedly connected to the wall of the detection groove (4). The limiting ring (13) is located between the sensing plate (5) and the sealing plate (6) and is close to the sealing plate (6). After the sealing plate (6) moves a set distance toward the sensing plate (5), it abuts against the limiting ring (13).

7. A device for detecting mold cavity pressure according to claim 1, 2, or 3, characterized in that, The lower mold (2) has several blind holes (202) at its top. A pressure sensor (14) is fixedly connected to the bottom of the blind hole (202). A counting rod (15) and a second elastic element (16) are inserted through the blind hole (202). The two ends of the second elastic element (16) act on the counting rod (15) and the hole wall of the blind hole (202) respectively. Under the action of the elastic force of the second elastic element (16), the top of the counting rod (15) extends out of the blind hole (202). When the upper mold (1) and the lower mold (2) are closed, the upper mold (1) causes the counting rod (15) to move downward against the elastic force of the second elastic element (16) and contact the pressure sensor (14).

8. A device for detecting mold cavity pressure according to claim 1, 2, or 3, characterized in that, The lower mold (2) also includes an outer mold (203) and a bottom mold (204). The outer mold (203) is detachably fixed to the bottom mold (204). The bottom of the outer mold (203) has a protruding anti-disassembly post (17), and the top of the bottom mold (204) has a recessed anti-disassembly hole (18). A trigger (19) is installed in the anti-disassembly hole (18). When the outer mold (203) and the bottom mold (204) are fixed together, the anti-disassembly post (17) extends into the anti-disassembly hole (18) and connects with the trigger (19). When the outer mold (203) and the bottom mold (204) are separated, the anti-disassembly post (17) leaves the anti-disassembly hole (18) and is separated from the trigger (19).

9. The device for detecting mold cavity pressure according to claim 8, characterized in that, The trigger (19) includes a connecting block (191) protruding and fixed to the inner wall of the anti-disassembly hole (18). A trigger rod (192) is hinged to the connecting block (191). A torsion spring (193) is provided between the connecting block (191) and the trigger rod (192), and the two ends of the torsion spring (193) act on the connecting block (191) and the trigger rod (192) respectively. When the outer mold (203) and the bottom mold (204) are fixed together, the trigger rod (192) abuts against the anti-disassembly post (17) under the action of the torsion of the torsion spring (193). When the outer mold (203) and the bottom mold (204) are separated, the anti-disassembly post (17) overcomes the torsion of the torsion spring (193) and separates from the trigger rod (192).

10. The device for detecting mold cavity pressure according to claim 8, characterized in that, The detection device includes a central control module (20) and a signal transmission module (21). The central control module (20) is embedded between the outer mold (203) and the bottom mold (204). The signal transmission module (21) is installed at the bottom of the bottom mold (204). The central control module (20) is electrically connected to the strain gauge (10), the trigger (19) and the signal transmission module (21).

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