Muffle end cover assembly for vacuum heat treatment furnace

Abstract

The utility model discloses a muffle end cover assembly for a vacuum heat treatment furnace, belongs to the technical field of vacuum heat treatment furnaces, and aims to solve the problem of how to improve the sealing reliability and durability in a high-temperature working environment. The muffle end cover assembly comprises an end cover which is provided with an inner side wall and an outer side wall, the center of the end cover is provided with a through hole extending in the axial direction, and the outer side wall is provided with two guide assemblies; the sealing door is parallel to the end cover and arranged on the inner side of the end cover, a first sleeve hole is formed in the center of the sealing door, and the sealing door and the end cover are arranged at an interval; the carbon-carbon composite material plate is parallel to the end cover and arranged on the outer side of the end cover, a second sleeve hole is formed in the center of the carbon-carbon composite material plate, the carbon-carbon composite material plate is strip-shaped, and the two ends of the carbon-carbon composite material plate slidably penetrate through the two guide assemblies; the connecting rod sequentially penetrates through the first sleeve hole of the sealing door, the through hole of the end cover and the second sleeve hole of the carbon-carbon composite material plate, the connecting rod can axially slide relative to the through hole of the end cover, and the connecting rod is fixedly connected with the sealing door and the carbon-carbon composite material plate.

Description

Technical Field

[0001] This application relates to the field of vacuum heat treatment furnace technology, and in particular to a muffle end cap assembly for a vacuum heat treatment furnace. Background Technology

[0002] In the high-temperature sintering process of powder metallurgy and ceramic products, the muffle end cap assembly of the sintering furnace is a key component for achieving furnace sealing and atmosphere protection. Traditional muffle end cap assemblies typically use a spring mechanism to apply preload to the sealing surface. For example, in existing technologies, axial clamping force is often provided by the bending deformation of helical springs or disc springs to ensure continuous clamping contact between the seal and the flange end face during the thermal expansion and deformation of the furnace.

[0003] However, such spring preload structures have the following drawbacks in practical applications: when the sintering furnace operates in a high-temperature environment for extended periods, the spring material is prone to high-temperature creep and stress relaxation, leading to a significant decrease in the elastic modulus. Especially under continuous operation, the residual deformation of the spring accumulates with increasing thermal cycles, eventually resulting in insufficient preload or even complete failure. This problem directly causes quality issues such as leakage of protective gas within the furnace, localized temperature field distortion, and oxidation of sintered products. Furthermore, spring failure necessitates shutdown for replacement, severely restricting continuous production capacity and increasing maintenance costs. Therefore, designing a high-temperature resistant, long-life muffle end cap preload mechanism is a pressing technical challenge in this field.

[0004] It should be noted that the information disclosed in the background section above is only used to enhance the understanding of the background of this disclosure, and therefore may include information that does not constitute prior art known to those skilled in the art. Utility Model Content

[0005] (a) Technical problems to be solved

[0006] This application provides a muffle end cap assembly for a vacuum heat treatment furnace, which can solve the problem of how to improve sealing reliability and durability in high-temperature working environments in the prior art.

[0007] (II) Technical Solution

[0008] To solve the above-mentioned technical problems, this application provides the following technical solution:

[0009] A muffle end cap assembly for a vacuum heat treatment furnace is provided, the muffle end cap assembly for the vacuum heat treatment furnace comprising: a muffle end cap assembly for sealing the inner furnace of the vacuum heat treatment furnace, characterized in that it comprises:

[0010] An end cap having opposing inner and outer sidewalls, an axially extending through hole at the center of the end cap, and two guide components on the outer sidewall;

[0011] A sealing door is parallel to the end cover and located inside the end cover, with a first set of holes in its center, spaced apart from the end cover.

[0012] A carbon-carbon composite material plate, parallel to the end cap and located on the outside of the end cap, has a second set of holes in its center, is long and strip-shaped, and its two ends can slide through the two guide components;

[0013] The connecting rod passes sequentially through the first set of holes of the sealing door, the through hole of the end cap, and the second set of holes of the carbon-carbon composite plate. The connecting rod is axially slidable relative to the through hole of the end cap. The connecting rod is fixedly connected to the sealing door and the carbon-carbon composite plate.

[0014] The sealing door is configured to translate toward the end cap when subjected to an external force toward the end cap, simultaneously driving the connecting rod to slide axially along the through hole, and causing the middle section of the carbon-carbon composite plate to bend away from the outside of the end cap while the two ends slide in the guide assembly and move closer to each other.

[0015] In some embodiments, the connecting rod is provided with a plurality of threaded segments, and a first nut is provided on each side of the sealing door and screwed onto one threaded segment of the connecting rod, and a second nut is provided on each side of the carbon-carbon composite plate and screwed onto the other threaded segment of the connecting rod.

[0016] In some embodiments, a mounting bracket is fixedly provided on the outer side of the end cap.

[0017] The mounting frame is provided with two sets of guide components. Each set of guide components includes a boss and a locking block. The boss is fixed on the mounting frame. The locking block is connected to the boss in the same set by bolts. The locking block has a guide groove on the side near the boss. The guide groove extends along the length of the carbon-carbon composite plate. Both ends of the carbon-carbon composite plate are slidably disposed in the guide groove.

[0018] In some embodiments, the carbon-carbon composite plate is tensioned parallel to the end cap.

[0019] In some embodiments, the mounting bracket includes a plurality of reinforcing rods arranged radially from the center of the end cap.

[0020] In some embodiments, the muffle end cap assembly for the vacuum heat treatment furnace further includes a rotating frame, the bottom end of which is connected to the mounting frame, and the top end of which extends above the end cap and is provided with a support rod; the vacuum heat treatment furnace further includes a frame and a drive mechanism, the support rod being fixedly connected to the frame, the support rod being configured to be rotatably connected to the frame of the sintering furnace and connected to the drive mechanism, the drive mechanism being configured to drive the rotating frame to rotate to open or close the end cap and the sealing door.

[0021] In some embodiments, the locking block has a connecting seat on the side opposite to the boss, and a crossbar is fixedly provided at the bottom end of the rotating frame. The end of the crossbar is rotatably connected to the connecting seat through a pin. A threaded rod is screwed to the bottom end of the rotating frame. One end of the threaded rod extends between the rotating frame and the mounting frame and is provided with a stop.

[0022] In some embodiments, the end cap has a groove on the side near the sealing door, a bushing is provided in the through hole, the groove surrounds the bushing and has a collar sleeved around the bushing inside, and a cover plate is provided at the end of the groove to cover the bushing and the collar. The groove is used to accommodate a first nut on the side of the sealing door near the end cap when the sealing door moves close to the end cap.

[0023] (III) Beneficial Effects

[0024] Compared with the prior art, the beneficial effects of the technical solution provided in this application include at least the following:

[0025] This application relates to a muffle end cap assembly for a vacuum heat treatment furnace. When the muffle end cap assembly needs to be moved to close the furnace body, and the sealing door is moved close to the inner furnace until it abuts against the inner furnace door frame, the sealing door is subjected to an impact force towards the end cap, causing the sealing door to move towards the end cap. Simultaneously, the connecting rod slides along the through hole of the end cap to push the carbon-carbon composite plate. Because the two ends of the carbon-carbon composite plate are limited by the guide components, they can only extend and retract along the length direction, while the middle section is relatively fixed to the connecting rod. When the carbon-carbon composite plate is pushed, the middle section undergoes bending deformation, allowing the impact force on the sealing door to be absorbed by the elastic deformation of the carbon-carbon composite plate. Through the bending deformation of the carbon-carbon composite plate, the impact force during closing can be effectively mitigated, preventing damage to the sealing door and end cap due to impact. At the same time, the carbon-carbon composite plate provides a continuous pre-tightening force through its own bending deformation, allowing the sealing door to smoothly fit against the inner furnace door frame when closed, and the sealing door can fit more tightly against the inner furnace, improving the sealing performance of the sintering furnace. The high strength and elasticity of carbon-carbon composite panels enable them to withstand repeated deformations without easily being damaged, thus extending the service life of the components. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a perspective view of the muffle end cap assembly for a vacuum heat treatment furnace in an embodiment of this application;

[0028] Figure 2 This is a side view of the muffle end cap assembly for a vacuum heat treatment furnace in an embodiment of this application;

[0029] Figure 3 yes Figure 2 A sectional perspective view of section A in the middle;

[0030] Figure 4 This is a top view of the muffle end cap assembly for a vacuum heat treatment furnace in an embodiment of this application;

[0031] Figure 5 yes Figure 4 A three-dimensional sectional view of section B.

[0032] Figure label:

[0033] End cap 1, through hole 11, bushing 12, groove 13, collar 14, mounting bracket 15, cover plate 16, boss 151, locking block 152, bolt 153, reinforcing rod 154, guide groove 155, connecting seat 156;

[0034] Connecting rod 2, smooth section 21, threaded section 22;

[0035] Sealing door 3, first hole 31, first nut 32;

[0036] Carbon-carbon composite plate 4, second sleeve hole 41, second nut 42;

[0037] Rotating frame 5, support rod 51, pin 52, crossbar 53, threaded rod 54, stop block 55;

[0038] Drive mechanism 6, frame 7.

[0039] The accompanying drawings illustrate specific embodiments of this application, which will be described in more detail below. These drawings and descriptions are not intended to limit the scope of the concept in any way, but rather to illustrate the concept of this application to those skilled in the art through reference to particular embodiments. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in further detail below with reference to the accompanying drawings.

[0041] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0042] When existing sintering furnaces operate in a high-temperature environment for extended periods, spring materials are prone to high-temperature creep and stress relaxation, leading to a significant decrease in elastic modulus. Particularly under continuous operation, the residual deformation of the springs accumulates with each thermal cycle, eventually resulting in insufficient preload or even complete failure. This problem directly causes quality issues such as leakage of protective gas within the furnace, localized temperature field distortion, and oxidation of sintered products. Furthermore, spring failure necessitates shutdown for replacement, severely restricting continuous production capacity and increasing maintenance costs.

[0043] To address the aforementioned technical problems, this embodiment provides a muffle end cap assembly for a vacuum heat treatment furnace. (See reference...) Figures 1 to 5 As shown, Figure 1 This is a perspective view of the muffle end cap assembly for a vacuum heat treatment furnace according to an embodiment of this application. Figure 2 This is a side view of the muffle end cap assembly for a vacuum heat treatment furnace in an embodiment of this application. Figure 3 yes Figure 2 Cross-sectional perspective view of section A. Figure 4 This is a top view of the muffle end cap assembly for a vacuum heat treatment furnace in an embodiment of this application. Figure 5 yes Figure 4 A three-dimensional sectional view of section B.

[0044] The muffle end cap assembly for a vacuum heat treatment furnace provided in this embodiment includes: end cap 1, connecting rod 2, sealing door 3, and carbon-carbon composite plate 4.

[0045] The muffle end cap assembly for the vacuum heat treatment furnace in this embodiment is suitable for a sintering furnace horizontally mounted on a support. The sintering furnace includes a furnace shell, a furnace body 8 inside the furnace shell, and an inner furnace 9 installed inside the furnace body 8. The inner furnace 9 provides space for vacuum sintering materials. A heating tube (which is prior art and will not be described or shown in the figure) is accommodated between the furnace body 8 and the inner furnace 9. One side of the sintering furnace has a furnace cover and an end cap 1 and a sealing door 3 installed inside the furnace cover. The furnace cover is used to close the furnace shell (not shown in the figure), the end cap 1 is used to close the furnace body 8, and the sealing door 3 is used to close the inner furnace 9. The furnace cover (not shown in the figure), the end cap 1, and the sealing door 3 are opened and closed horizontally. The end cap 1 has opposing inner and outer side walls, wherein the inner side wall of the end cap 1 faces the inside of the furnace body 8, and the outer side wall of the end cap faces the outside of the furnace body 8.

[0046] The end cap 1 has an axially extending through hole 11 at its center. Two guide components are provided on the outer side wall of the end cap 1, which are used to guide the end of the carbon-carbon composite plate 4.

[0047] For example, a bushing 12 is provided inside the through hole 11, and the bushing 12 is installed inside the through hole 11 in an existing manner.

[0048] The sealing door 3 is a door smaller than the end cover 1, and is used to seal the inner furnace 9. The sealing door 3 is located inside the end cover 1, and has a first sleeve hole 31 in its center. It is spaced a certain distance from the end cover 1 and is set parallel to the end cover 1.

[0049] The carbon-carbon composite material plate 4 is long and narrow, parallel to the end cap 1 and located on the outer side wall of the end cap 1, with a second hole 41 in its center.

[0050] The connecting rod 2 passes sequentially through the first hole 31 of the sealing door 3, the through hole 11 of the end cap 1, and the second hole 41 of the carbon-carbon composite plate 4. The connecting rod 2 can slide axially relative to the through hole 11 of the end cap 1. The connecting rod 2 is fixedly connected to the sealing door 3 and the carbon-carbon composite plate 4.

[0051] When the sealing door 3 is configured to be moved close to the inner furnace 9 to the door frame of the inner furnace when subjected to an external force toward the end cover 1, for example when the inner furnace 9 needs to be closed, the sealing door 3 is subjected to an impact force toward the end cover 1 and moves in a direction closer to the end cover 1. Simultaneously, the connecting rod 2 slides axially along the through hole 1, and the middle section of the carbon-carbon composite plate 4 bends away from the outer side of the end cover 1 and the two ends slide in the guide assembly and move closer to each other.

[0052] The connecting rod 2 has several threaded sections. The sealing door 1 has a first nut 32 on each side, which is threaded and tightened onto one threaded section of the connecting rod 2. The carbon-carbon composite plate 4 has a second nut 42 on each side, which is threaded and tightened onto the other threaded section of the connecting rod 2.

[0053] For example, the connecting rod 2 includes a smooth section 21 and two threaded sections 22 formed by axially extending from both ends of the smooth section 21. The smooth section 21 passes through the through hole 11 of the end cap 1 and is axially slidably disposed within the bushing 12. The two threaded sections 22 extend to the outer sides of the inner and outer sides of the end cap 1. The sealing door 3 is sleeved on the threaded section 22 on the inner side of the end cap 1 through the first sleeve hole 31. The sealing door 3 is provided with first nuts 32 on both sides of the first sleeve hole 31, and the sealing door 3 is fixed on the threaded section 22 by tightening the first nuts 32. The carbon-carbon composite plate 4 is sleeved on the threaded section 22 on the outer side of the end cap 1. The carbon-carbon composite plate 4 is provided with second nuts 42 on both sides of the second sleeve hole 41, and the carbon-carbon composite plate 4 is fixed on the threaded section 22 by tightening the second nuts 42.

[0054] For example, carbon-carbon composite plate 4 is an existing carbon composite plate made of carbon fiber or graphite fiber as reinforcement and carbon or graphite as matrix, which is carbonized.

[0055] In some implementations, see Figure 1 and Figure 3 As shown, an installation bracket 15 is fixedly mounted on the side of the end cap 1 away from the sealing door 3. The installation bracket 15 has two sets of guide components, each set including a boss 151 and a locking block 152. For example, two bosses 151 are fixed to the installation bracket 15 by welding or integral molding. Each of the two bosses 151 is detachably equipped with a locking block 152, which is a separate component from the boss 151. A guide groove 155 is provided on the side of the locking block 152 near the boss 151. The guide groove 155 extends along the length of the carbon-carbon composite plate 4, and both ends of the carbon-carbon composite plate 4 are slidably disposed within the guide groove 155. The guide groove 155 extends along the length of the carbon-carbon composite plate 4, and the locking block 152 and the boss 151 achieve directional movement of both ends of the carbon-carbon composite plate 4 through the guide groove 155. The two ends of the carbon-carbon composite plate 4 are slidably disposed within the guide groove 155, while simultaneously preventing the carbon-carbon composite plate 4 from flipping over. The locking block 152 and the boss 151 are set separately and connected by bolts 153 to achieve quick disassembly and assembly, so that the replacement of carbon-carbon composite plate 4 does not require disassembling the entire end cover 1, thus improving maintenance efficiency.

[0056] Further, see Figure 1As shown, the mounting bracket 15 includes a plurality of reinforcing rods 154 arranged radially from the center of the end cap 1. Exemplarily, the reinforcing rods 154 form a cross or star-shaped structure. The reinforcing rods 154 can improve the structural strength of the end cap 1, and the radial layout is beneficial for dispersing thermal stress concentration.

[0057] For easier control of the opening and closing of end cap 1 and sealing door 3, please refer to... Figure 1 and Figure 2 As shown, the muffle end cap assembly also includes a rotating frame 5, the bottom end of which is connected to the mounting frame 15, the top end of which extends above the end cap 1 and is fixedly provided with a support rod 51. The support rod 51 is configured to be rotatably connected to the frame 7 of the sintering furnace and connected to a drive mechanism 6 installed on the sintering furnace. The drive mechanism 6 is configured to drive the rotating frame 5 to rotate in order to open or close the end cap 1 and the sealing door 3. For example, the drive mechanism 6 is a cylinder installed on the frame 7, and the cylinder pushes the rotating frame 5 to rotate around the frame 7.

[0058] It is understandable that there is a certain gap between the cover plate 16 and the first nut 32, and between the second nut 42 and the bushing 12, to avoid interfering with the movement of the connecting rod 2.

[0059] The frame 7 is located inside the furnace cover of the sintering furnace, for example, at the top of the inside of the furnace cover.

[0060] In one embodiment where the bottom end of the rotating frame 5 is connected to the mounting frame 15, see [reference needed]. Figure 1 and Figure 3 As shown, the locking block 152 has a connecting seat 156 on the side opposite to the boss 151. A crossbar 53 is fixed at the bottom of the rotating frame 5. The two ends of the crossbar 53 are rotatably connected to the two connecting seats 156 through pins 52. A threaded rod 54 is screwed to the bottom of the rotating frame 5. One end of the threaded rod 54 extends between the rotating frame 5 and the mounting frame 15 and is provided with a stop 55. When the rotating frame 5 rotates around the machine frame 7, it pushes the end cover 1 and the sealing door 3 to close. The sealing door 3 can adaptably rotate around the pin 52 to fit the inner furnace 9. The threaded rod 54 can adjust the position of the stop 55 by changing the screw depth, which can precisely control the final clamping force when the end cover 1 is closed. The adjustment accuracy is higher than that of the traditional gasket structure.

[0061] like Figure 3 As shown, it can be understood that the rotating frame 5 has clearance holes or spaces required for the movement of the connecting rod 2, such as clearance holes on the crossbar 53, in order to avoid interfering with the normal movement of the connecting rod 2.

[0062] In some implementations, see Figure 3 and Figure 5As shown, the end cap 1 has a groove 13 near the sealing door 3. The groove 13 surrounds the bushing 12 and has a collar 14 fitted around the bushing 12 inside. The end of the groove 13 has a cover plate 16 that seals the bushing 12 and the collar 14. For example, the cover plate 16 and the collar 14 are fixed to the end cap 1 by bolts to restrict the movement of the bushing 12 and achieve a sealing effect.

[0063] It is understandable that there is a certain gap between the cover plate 16 and the first nut 32, and between the second nut 42 and the bushing 12 (not shown in the figure due to the small gap), which allows the connecting rod 2 to move when the sealing door 3 is subjected to external force.

[0064] In summary, when the muffle end cap assembly for the vacuum heat treatment furnace of this application is in operation, if the furnace body 8 needs to be closed and the sealing door 3 and end cap 1 are driven by the drive device to move close to the furnace body 8, and the sealing door 3 is pushed against the door frame of the inner furnace (furnace chamber), the sealing door 3 is subjected to an impact force towards the end cap 1, causing the sealing door 3 to move towards the end cap. Simultaneously, the connecting rod 2 slides along the through hole 11 of the end cap to push the carbon-carbon composite plate 4. Since the two ends of the carbon-carbon composite plate 4 are limited by the guide assembly, it can only extend and retract along the length direction, and the middle section is relatively fixed with the connecting rod 2. When the carbon-carbon composite plate 4 is pushed, the middle section undergoes bending deformation, so that the impact force on the sealing door 3 is absorbed by the elastic deformation of the carbon-carbon composite plate 4. Through the bending deformation of the carbon-carbon composite plate 4, the impact force when the sealing door 3 is closed can be effectively mitigated, and damage to the sealing door 3 and end cap 1 due to impact can be avoided. Meanwhile, the carbon-carbon composite plate 4 provides continuous pre-tightening force through its own bending deformation, allowing the sealing door 3 to smoothly fit against the inner furnace door frame when closed, and the sealing door 3 can fit more tightly against the inner furnace, improving the sealing performance of the sintering furnace. The high strength and elasticity of the carbon-carbon composite plate 4 enable it to withstand repeated deformation without easily being damaged, thereby extending the service life of the components.

[0065] The above description is merely an optional embodiment of this application and is not intended to limit this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A muffle end cap assembly for a vacuum heat treatment furnace, the muffle end cap assembly for sealing a furnace body of the vacuum heat treatment furnace, characterized in that, The utility model relates to a muffle end cover assembly for vacuum heat treatment furnace, comprising: an end cover having opposite inner and outer sidewalls, the end cover having an axially extending through hole in the center thereof, the outer sidewall having two guide assemblies; a sealing door parallel to the end cover and disposed on the inner side of the end cover, the sealing door having a first sleeve hole in the center thereof and spaced apart from the end cover; a carbon-carbon composite plate parallel to the end cover and disposed on the outer side of the end cover, the carbon-carbon composite plate having a second sleeve hole in the center thereof and in the shape of a long strip, the two ends of the carbon-carbon composite plate being slidably disposed in the two guide assemblies; a connecting rod sequentially passing through the first sleeve hole of the sealing door, the through hole of the end cover and the second sleeve hole of the carbon-carbon composite plate, the connecting rod being axially slidable relative to the through hole of the end cover, the connecting rod being fixedly connected to the sealing door and the carbon-carbon composite plate; the sealing door being configured to translate towards the end cover when subjected to an external force towards the end cover, the sealing door simultaneously driving the connecting rod to axially slide along the through hole and causing the middle section of the carbon-carbon composite plate to bend away from the outer side of the end cover and the two ends of the carbon-carbon composite plate to slide in the guide assemblies and move towards each other.

2. The muffle end cover assembly for a vacuum heat treatment furnace of claim 1, wherein, the connecting rod having a plurality of threaded sections, each of the two sides of the sealing door having a first nut threadedly screwed on one of the threaded sections of the connecting rod, each of the two sides of the carbon-carbon composite plate having a second nut threadedly screwed on another one of the threaded sections of the connecting rod.

3. The muffle end cover assembly for a vacuum heat treatment furnace of claim 1, wherein, the outer side of the end cover being fixedly provided with a mounting rack, the mounting rack having two sets of guide assemblies, each set of guide assemblies comprising a boss and a locking block, the boss being fixedly provided on the mounting rack, the locking block being connected to the boss of the same set through a bolt, the locking block being provided with a guide groove on the side close to the boss, the guide groove extending along the length direction of the carbon-carbon composite plate, the two ends of the carbon-carbon composite plate being slidably disposed in the guide groove.

4. The muffle end cover assembly for a vacuum heat treatment furnace of claim 3, wherein, the carbon-carbon composite plate being tensioned parallel to the end cover.

5. The muffle end cover assembly for a vacuum heat treatment furnace of claim 3, wherein, the mounting rack comprising a plurality of reinforcing rods radially arranged with the center of the end cover as the starting point.

6. The muffle end cover assembly for a vacuum heat treatment furnace of claim 3, wherein, the muffle end cover assembly further comprising a rotating frame, the bottom end of the rotating frame being connected to the mounting rack, the top end of the rotating frame extending above the end cover and being provided with a support rod, the vacuum heat treatment furnace further comprising a rack and a driving mechanism, the support rod being fixedly connected to the rack, the support rod being configured to be rotatably connected to the rack of the sintering furnace and connected to the driving mechanism, the driving mechanism being configured to drive the rotating frame to rotate so as to open or close the end cover and the sealing door.

7. The muffle end cover assembly for a vacuum heat treatment furnace of claim 6, wherein, the side of the locking block away from the boss being provided with a connecting seat, the bottom end of the rotating frame being fixedly provided with a horizontal rod, the end of the horizontal rod being rotatably connected to the connecting seat through a pin, the bottom end of the rotating frame being screwed with a threaded rod, one end of the threaded rod extending between the rotating frame and the mounting rack and being provided with a stopper.

8. The muffle end cover assembly for a vacuum heat treatment furnace of claim 3, wherein, the side of the end cover close to the sealing door being provided with a groove, the through hole being provided with a shaft sleeve, the groove being arranged around the shaft sleeve and being internally provided with a sleeve ring sleeved on the periphery of the shaft sleeve, the end of the groove being provided with a cover plate covering the shaft sleeve and the sleeve ring, the groove being used to accommodate the first nut on the side of the sealing door close to the end cover when the sealing door moves close to the end cover.

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