CN106965311B - A top-out tube extruding type ceramic tube forming machine - Google Patents

Abstract

The extrusion driving mechanism assembly consists of a spiral transmission shaft, a spiral push-pull moving disc, a push-pull rod, a piston mud pressing plate, a driven large sprocket wheel and a radial stress bearing, the speed reduction driving motor rotates the spiral transmission shaft through the sprocket wheel and enables the spiral push-pull moving disc to move upwards, the push-pull rod fixed on the spiral push-pull moving disc enables the piston mud pressing plate positioned in the outer die tube to move upwards, ceramic tube pugs in the inner die core and the outer die tube are extruded into ceramic tube green bodies along annular gaps formed by the inner die core and the outer die tube under the combined action of the piston mud pressing plate and the rotating inner die core.

Description

A kind of extrusion type ceramic tube forming machine with upper discharge tube

technical field

The invention belongs to the technical field of forming inorganic non-metallic materials, and in particular relates to an upper discharge pipe extruding type ceramic pipe forming machine.

Background technique

The existing spiral extrusion molding equipment for ceramic tube mud blanks is directly in contact with the mud because the screw propeller blades are in direct contact with the mud. The extrusion force of the mud into the billet comes from the friction between the mud and the spiral blades. It is directly affected by the properties of the mud, not only that, if there is no vacuum equipment in the conventional technology to release the gas in the mud gap, affected by the way and nature of the extrusion force of the screw blade of the extruder, the gas in the mud gap and The mud moves together and cannot be completely removed from the mud, and the green body of the ceramic tube is loose. Therefore, the conventional screw extrusion molding equipment has strict requirements on the quality of the mud. When there is no external vacuum exhaust equipment, the density of the ceramic tube green body extruded has quality defects such as looseness, high moisture, and cracking. In addition, the horizontal screw extrusion During the production of the forming equipment, the quality defect of the ceramic tube green body falling off due to the flattening or deformation of the tube blank due to its own weight when the tube blank is lying down, the mold casting equipment has complex equipment procedures, high water content of the tube blank, and long demoulding time. The defects of low efficiency, easy deformation during drying, large body shrinkage during firing, and easy cracking.

Contents of the invention

Purpose of the invention of the present invention:

Mainly aiming at the above situation, in order to overcome the defects of the prior art, the purpose of the present invention is to provide a kind of clay with high density, high circularity and low water content, which has strict requirements on the quality of the mud and can be extruded without external vacuum exhaust equipment. Ceramic tube green body, which overcomes the disadvantages of easy deformation of ceramic tube green body, large body shrinkage during firing, and easy cracking.

Technical scheme of the present invention is:

Provided is an upper outlet tube extruding type ceramic tube forming machine, including a frame, an extrusion transmission mechanism assembly, an inner mold core, an outer mold tube and a deceleration drive motor, and the frame consists of a base, four support columns, anti-collision rubber Column, motor connection fixed plate, outer mold tube lower support seat, outer mold upper pressure plate and axial force bearing seat, the base is a rectangular frame, and there are multiple reinforcing ribs between the upper plate and the lower plate of the frame and a cylindrical reinforced round tube, four tubular frame legs are provided at the four corners under the lower plate of the frame body, a reduction drive motor output shaft through hole is provided on the upper plate and the lower plate of the frame body, a Squeeze the through hole of the transmission mechanism component and a plurality of fixing screw holes of the motor connection plate. There are also four fixing through holes for the supporting column on the upper plate. The supporting column is inserted and fixed in the fixing through hole of the supporting column. Anti-collision rubber column, the anti-collision rubber column is placed on the surface of the upper plate, and the through hole of the extrusion transmission mechanism assembly on the base is equipped with an axial force bearing whose central axis coincides with the axis of the extrusion transmission mechanism assembly hole axis Seat, the axial force bearing seat is inserted with the extruded transmission mechanism assembly, the motor connection fixed plate is fixed on the through hole of the output shaft of the deceleration drive motor on the base through screws, and the central axis of the output shaft of the deceleration drive motor is connected to the shaft through the hole. The central axis of the stressed bearing seat is parallel to and perpendicular to the surface of the upper plate. The central axes of the four supporting columns are evenly distributed on the pitch circle centered on the center of the through hole of the extrusion transmission mechanism assembly. The supporting columns The upper thin section is provided with connecting threads, the middle transition section is provided with fastening threads, and the end of the lower thick section is provided with a stepped round bar with an external thread boss whose diameter is smaller than that of the thick section. The lower support seat of the outer mold tube is designed A square plate with a cylindrical boss. The boss is provided with a stepped radial force bearing fixing through hole, and the end surface of the square plate is also provided with four support column through holes matching the fastening thread of the middle transition section of the support column. , the cylindrical boss of the lower support seat of the outer mold tube is also provided with a plurality of push-pull rod through holes, the axes of the support column through holes and the push-pull rod through holes are all perpendicular to the end face of the cylindrical boss, and the upper pressure plate of the outer mold is set in the middle part. A square plate with a transparent round hole. The corner of the upper pressure plate of the outer mold is provided with a transparent round hole matching the thin thread on the upper part of the supporting column. The extrusion transmission mechanism assembly consists of a screw drive shaft, a screw push-pull moving plate, and a push-pull rod. , piston mud plate, driven large sprocket and radial force bearing, the screw drive shaft is a stepped shaft with a drive screw in the middle, and the lower part of the upper part of the screw drive shaft is equipped with a diameter matching the lower support seat of the outer mold tube. To the force bearing, the upper end surface of the screw drive shaft is also provided with a square concave hole, the center of the square concave hole is provided with an inner mold core connecting thread counterbore, the lower part of the screw drive shaft is provided with a shaft shoulder and an optical axis, and the lower end of the optical axis There is a keyway on the part of the screw drive shaft, and the driven large sprocket is fixed on the keyway part of the screw drive shaft. The center of the moving plate is provided with a spiral through hole matching the transmission helical section of the screw drive shaft, and the spiral push-pull moving plate is also provided with four column through holes matching the support column and a plurality of push-pull rod fixing through holes. Push-pull rods are inserted into the fixing through holes of the tie rods. The push-pull rods are stepped rods with threads at both ends. The piston mud pressing plate is a ring-shaped disc. There are a plurality of push-pull rod fixed threaded sink holes on the lower end of the piston mud plate, the upper end of the push-pull rod is screwed into the fixed thread counterbore of the piston mud plate, and the lower threaded counterbore of the push-pull rod The push-pull rod fixing through hole of the push-pull movable disk is fixed together with the screw push-pull movable disk by nuts, the upper surface of the piston mud plate is perpendicular to the central axis of the screw drive shaft, and the deceleration drive motor is fixed on the base through the motor connection fixed disk. On the plate, a small sprocket is fixed on the output shaft of the deceleration drive motor, and the small sprocket is connected with the driven large sprocket through the transmission chain. The pipe is a hollow cylinder with a feeding pipe on the side. The inner diameter of the outer mold pipe matches the outer diameter of the cylindrical boss of the lower support seat of the outer mold pipe. The outer end of the feeding pipe is provided with a feeding control valve. The inner mold core is the upper Large and small rotating body, the upper part of the rotating body is cylindrical, the lower end surface of the inner mold core is provided with a square boss matching the square concave hole in the upper end surface of the screw drive shaft, and the upper end of the inner mold core is provided with a stepped tight Fixing screw insertion holes, the square boss of the inner mold core is inserted in the square concave hole on the upper end surface of the screw drive shaft, and fixed together with the screw drive shaft through the fastening screws.

The beneficial effects of the present invention are:

The invention has the advantages of simple equipment, low water content of the extruded tube blank, short demoulding time, high efficiency, no deformation during drying, small shrinkage of the blank during firing, and no cracking.

Description of drawings

Fig. 1 is a front sectional view of the present invention.

Fig. 2 is a structural schematic diagram of the frame of the present invention.

Fig. 3 is a structural schematic diagram of the bottom plate of the present invention.

Fig. 4 is a top sectional view of the bottom plate of the present invention.

Fig. 5 is a top view of the bottom plate of the present invention.

Fig. 6 is a structural schematic diagram of the motor connection fixed plate of the present invention.

Fig. 7 is a structural schematic diagram of the lower support seat of the outer mold tube of the present invention.

Fig. 8 is a schematic structural view of the upper pressing plate of the outer mold of the present invention.

Fig. 9 is a cross-sectional view of the extrusion transmission mechanism assembly of the present invention.

Fig. 10 is a schematic structural view of the spiral push-pull moving plate of the present invention.

Fig. 11 is a schematic structural view of the piston pressing mud plate of the present invention.

Fig. 12 is a schematic structural view of the inner mold core of the present invention.

Among them: 1 is the frame; 2 is the extrusion transmission mechanism assembly; 3 is the inner mold core; 4 is the outer mold tube; 5 is the deceleration drive motor; 6 is the base; 7 is the support column; 8 is the anti-collision rubber column; 9 10 is the lower support seat of the outer mold tube; 11 is the upper pressure plate of the outer mold; 12 is the axial force bearing seat; 13 is the upper plate; 14 is the lower plate; 15 is the reinforced cylinder; 16 is the tubular Frame legs; 17 is the through hole of the output shaft of the deceleration drive motor; 18 is the through hole of the extrusion transmission mechanism assembly; 19 is the fixing through hole of the supporting column; 20 is the fixing through hole of the radial force bearing; 21 is the through hole of the supporting column; 22 is a push-pull rod through hole; 23 is a screw drive shaft; 24 is a spiral push-pull moving plate; 25 is a push-pull rod; 26 is a piston mud plate; 27 is a driven large sprocket wheel; Small sprocket wheel; 30 is a feeding pipe; 31 is a feeding control valve; 32 is a fastening screw insertion hole; 33 is a reinforcing rib foot plate.

Detailed ways

The specific implementation manners of the present invention will be described in further detail below in conjunction with the accompanying drawings.

Given by Figures 1 to 12, the present invention includes a frame 1, an extrusion transmission mechanism assembly 2, an inner mold core 3, an outer mold tube 4 and a deceleration drive motor 5, and the frame 1 is composed of a base 6 and four supporting columns 7 , anti-collision rubber column 8, motor connection fixed plate 9, outer mold tube lower support seat 10, outer mold upper pressure plate 11 and axial force bearing seat 12 constitute, the base 6 is a rectangular frame body, the upper plate 13 of the frame body and A plurality of stiffener plates and a cylindrical reinforced pipe 15 are arranged between the lower plates 14, four tubular frame legs 16 are arranged at four corners below the lower plate 14 of the frame, the upper plate 13 and the frame of the frame are The lower plate 14 is provided with a reduction drive motor output shaft through hole 17, an extrusion transmission mechanism component through hole 18 and a plurality of motor connection plate fixing screw holes, and the upper plate 13 is also provided with four support column fixing through holes. 19, the support column fixing through hole 19 is inserted and fixed with a support column 7, and the lower part of the support column 7 is equipped with an anti-collision rubber column 8, and the anti-collision rubber column 8 is placed on the board surface of the upper plate 13, and the extrusion on the base 6 The through hole 18 of the pressing transmission mechanism component is equipped with an axial force bearing seat 12 whose central axis coincides with the axis of the extrusion transmission mechanism component through hole 18, and the axial force bearing seat 12 is inserted with the extrusion transmission mechanism component 2 , the motor connection fixed plate 9 is fixed on the through hole 17 of the output shaft of the deceleration drive motor on the base 6 via screws, the central axis of the output shaft through hole 17 of the deceleration drive motor is parallel to the central axis of the axially stressed bearing seat 12 and is parallel to the The upper plate 13 is vertical, and the central axes of the four supporting columns fixing through holes 19 are evenly distributed on the pitch circle centered on the center of the through hole 18 of the extrusion transmission mechanism assembly, and the supporting columns 7 are provided with connecting threads for the upper thin section. 1. The middle transition section is provided with fastening threads, and the end of the lower thick section is provided with a step-shaped round bar with an external thread boss whose diameter is smaller than that of the thick section. The lower support seat 10 of the outer mold tube is a square plate with a cylindrical boss. , the boss is provided with a step-shaped radial force bearing fixing through hole 20, and the end face of the square plate is also provided with four support column through holes 21 that match the fastening thread of the middle transition section of the support column 7, and the outer mold tube The cylindrical boss of the lower support seat 10 is also provided with a plurality of push-pull rod through holes 22, the axes of the support column through holes 21 and the push-pull rod through holes 22 are perpendicular to the end face of the cylindrical boss, and the upper pressing plate 11 of the outer mold is the middle part. A square disc with a transparent round hole, the corner of the upper platen 11 of the outer mold is provided with a transparent round hole matching the thin thread on the upper part of the support column 7, the extrusion transmission mechanism assembly 2 is composed of a screw drive shaft 23, a screw push-pull The moving plate 23, the push-pull rod 25, the piston mud pressing plate 26, the large driven sprocket 27 and the radial force bearing 28 are composed of a screw drive shaft 23 which is a stepped shaft with a drive screw in the middle, and the lower section of the upper part of the screw drive shaft is set There is a radial force bearing 28 matched with the lower support seat 10 of the outer mold tube, and a square concave hole is also provided on the upper end surface of the screw drive shaft 23, and the center of the square concave hole is provided with an inner mold core connecting thread counterbore, and the screw drive The lower part of the shaft 23 is provided with a shaft shoulder and an optical shaft, the lower end of the optical shaft is provided with a keyway, the keyway on the screw drive shaft 23 is fixed with a driven large sprocket 27, and the external rotation of the drive screw of the screw drive shaft 23 is equipped with a screw push-pull movement Disk 23, the spiral push-pull movable disk 23 is a square disk provided with a cylindrical boss, the center of the spiral push-pull movable disk 23 is provided with a spiral through hole matched with the transmission helical section of the screw transmission shaft 23, and the spiral push-pull movable disk 23 is also provided with There are four column via holes matching the support column 7 and a plurality of push-pull rod fixing through holes, each push-pull rod fixing through-hole is equipped with a push-pull rod 25, and the push-pull rod 25 is a stepped shape with threads at both ends. The rod member, the piston mud plate 26 is an annular disc, the central part of the piston mud plate 26 is provided with a via hole matching the upper section of the screw transmission shaft 23, and the lower end surface of the piston mud plate 26 is provided with a plurality of pushing holes. The pull rod fixes the threaded counterbore, the upper end of the push-pull rod 25 is screwed into the fixed threaded counterbore of the piston mud plate 26, and the lower end of the push-pull rod 25 passes through the push-pull fixed through hole of the screw push-pull moving plate 23 and is connected by the nut and the screw push-pull moving plate. 23 are fixed together, the upper surface of the piston mud pressing plate is perpendicular to the central axis of the screw transmission shaft, the deceleration drive motor 5 is fixed on the upper plate 13 of the base 6 through the motor connection fixed plate 9, and the deceleration drive motor 5 is fixed on the output shaft There is a small sprocket 29, the small sprocket 29 is connected to the driven large sprocket 27 through the transmission chain, and the outer mold tube 4 is fixed between the lower support seat 10 of the outer mold tube and the upper pressing plate 11 of the outer mold, and the outer mold tube 4 is the side surface A hollow cylinder with a feeding pipe 30, the inner diameter of the outer mold pipe 4 matches the outer diameter of the cylindrical boss of the lower support seat 10 of the outer mold pipe, the outer end of the feeding pipe 30 is provided with a feeding control valve 31, and the inner mold core 3 is a rotating body with a large top and a small bottom. The upper part of the rotating body is cylindrical. The lower end surface of the inner mold core 3 is provided with a square boss matching the square concave hole in the upper end surface of the screw drive shaft 23. The inner mold core 3 The upper end is provided with a stepped fastening screw insertion hole 32, and the square boss of the inner mold core 3 is inserted into the square concave hole on the upper end surface of the screw drive shaft 23, and is fixed together with the screw drive shaft 23 by the fastening screw.

The middle part under the long sides of the frame body is provided with two stiffener feet 33 .

A backing plate is provided under the tubular frame leg 16 .

Embodiment 1: When the present invention is used, the base 6 of the frame 1 is installed and fixed, the axially stressed bearing seat 12 is fixed on the upper plate 13 of the base 6, and the screw drive shaft 23 is inserted into the axially stressed In the bearing seat 12, the spiral push-pull moving disc 24 is screwed onto the screw transmission shaft 23, and then the support column 7 is inserted and fixed on the upper plate 13 of the base 6 through the spiral push-pull moving disc 24 and the anti-collision rubber column 8, and then installed Fix the lower support base 10 of the outer mold, the upper pressure plate 11 of the outer mold, connect the piston pressing plate 26, the push-pull rod 25, and the screw push-pull moving plate 24, and install the square boss difference of the inner mold core 3 into the screw drive In the square concave hole on the upper end surface of the shaft 23 and fixed on the upper end of the screw transmission shaft 23, the deceleration drive motor 5, the motor connection fixing plate 9 and the base 6 of the frame 1 are connected and fixed, and then the output shaft of the deceleration drive motor 5 Install the small sprocket 29 on the top, and connect the small sprocket 29 with the driven large sprocket 27 with a transmission chain. When squeezing the pipe, first make the piston mud pressing plate 26 at the lowest position, open the feeding control valve 31 and add the mud material In the outer mold tube 4, start the deceleration drive motor 5, and the driven large sprocket 27 rotates under the drive of the small sprocket 29. At this time, the screw drive shaft 23 also rotates with the driven large sprocket 27, and the screw drive shaft 23 drives The spiral push-pull moving plate 24 moves on the constraint guide of the four supporting columns 7, and the push-pull rod 25 fixed on the spiral push-pull moving plate 24 drives the piston pressing plate 26 in the outer mold tube 4 to move upward, and squeezes the outer mold tube The mud material in 4 flows into the inner mold core 3 and the outer mold tube 4 to form an annular gap. At the same time, the inner mold core 3 fixed on the end of the screw drive shaft 23 rotates together with the screw drive shaft 23, and the mud material inside The space between the mold core 3 and the outer mold tube 4 is moved upward by the axial upward extrusion force of the piston pressing plate 26, and is extruded under the constraint of the outer mold tube 4 to become the maximum outer diameter of the inner diameter and the inner mold core 3. The ceramic tube green body with the same diameter and the same outer diameter as the inner diameter of the outer mold tube 4. In the embodiment, the processed mud material is bound by the inner mold core 3, the inner wall of the outer mold tube 4, and the piston pressing mud plate 26. The extrusion force of the billet is mainly from the pushing force of the piston mud plate 26, so that the volume of the mud can be shrinked and compacted, and at the same time, the gas in the gap of the mud can be removed from the gap between the 3 walls of the inner mold core and the mud, and Because the inner mold core 3 rotates under the drive of the screw drive shaft 23, not only the resistance to the axial movement of the mud and the green body is reduced, but also the wall rotation of the inner mold core 3 and the mud generate tangential friction, and the tangential friction is the same as that of the mud. The resultant force from the axial pushing force of the push piston mud plate 26 makes the mud generate radial and circumferential compaction force, the forming extrusion force is no longer affected by the properties of the mud material, and at the same time has the advantage of the axial compaction force of the spiral blade , so that mud with low water content can be used, the extruded tube billet has low water content, high density, not easy to deform when dry, small shrinkage when firing, and not easy to crack. In addition, because the outer mold tube is in the vertical Extrusion not only ensures the circularity of the outer diameter of the ceramic green body and avoids the deformation of the horizontal extrusion green body, but the rotation of the inner core makes the circularity of the inner diameter of the ceramic tube green body better, so the ceramic tube The circularity of the green body is good.

The invention has simple equipment, and the extruded tube billet has low water content and high roundness, is not easily deformed during drying, has small shrinkage and is not easy to crack when fired.

Claims (1)

1. An upper outlet pipe extrusion type ceramic pipe forming machine comprises a frame (1), an extrusion transmission mechanism assembly (2), an inner mold core (3), an outer mold pipe (4) and a speed reduction driving motor (5), and is characterized in that the frame (1) is composed of a base (6), four supporting columns (7), an anti-collision rubber column (8), a motor connection fixing disc (9), an outer mold pipe lower supporting seat (10), an outer mold upper pressing plate (11) and an axial stress bearing seat (12), the base (6) is a rectangular frame body, a plurality of reinforcing rib plates and a cylindrical reinforcing round tube (15) are arranged between an upper plate (13) and a lower plate (14) of the frame body, four tubular frame legs (16) are arranged at four corners below the lower plate (14) of the frame body, a speed reduction driving motor output shaft through hole (17), an extrusion transmission mechanism assembly through hole (18) and a plurality of motor fixing screw holes are formed in the upper plate (13), four supporting column fixing through holes (19) are further formed in the upper plate (13), a rubber column fixing connection disc (7) is inserted into the upper plate (8) of the anti-collision rubber column fixing disc (8), an axial stress bearing seat (12) with a central axis coincident with the axis of the extrusion transmission mechanism assembly through hole (18) is arranged at the extrusion transmission mechanism assembly through hole (18) on the base (6), the extrusion transmission mechanism assembly (2) is inserted in the axial stress bearing seat (12), a motor connecting fixing disc (9) is fixed on a speed reduction driving motor output shaft through hole (17) on the base (6) through a screw, the central axis of the speed reduction driving motor output shaft through hole (17) is parallel to the central axis of the axial stress bearing seat (12) and vertical to the surface of the upper plate (13), the central axes of four support column fixing through holes (19) are uniformly distributed on a pitch circle taking the center of the extrusion transmission mechanism assembly through hole (18) as the center of a circle, the support column (7) is provided with connecting threads on the upper part, the middle transition section is provided with fastening threads, the end part of the lower section is provided with a step-shaped round bar with an external thread boss with diameter smaller than the diameter of the thick section, a square disc with a step-shaped radial stress bearing fixing through hole (20) is arranged in the boss, the square disc is also provided with four support column (7) through holes (21) and a plurality of support column through holes (22) are arranged on the end faces of the square disc, the support column through holes are matched with the support column through holes (21), the external mold upper pressing plate (11) is a square disk with a through round hole in the middle part, the corner part of the external mold upper pressing plate (11) is provided with a through round hole matched with the thin section thread on the upper part of the supporting upright post (7), the extrusion transmission mechanism component (2) is composed of a spiral transmission shaft (23), a spiral push-pull moving disk (24), a push-pull rod (25), a piston mud pressing plate (26), a driven large sprocket (27) and a radial stress bearing (28), the spiral transmission shaft (23) is a square disk with a step shaft with a transmission spiral in the middle part, the lower section of the upper part of the spiral transmission shaft is sleeved with the radial stress bearing (28) matched with the lower supporting seat (10) of the external mold pipe, the upper end surface of the spiral transmission shaft (23) is also provided with a square concave hole, the center of the square concave hole is provided with an internal mold core connecting threaded counter bore, the lower part of the spiral transmission shaft (23) is provided with a shaft shoulder and an optical axis, the lower end part of the optical axis is provided with a key slot, the key slot part on the spiral transmission shaft (23) is fixedly provided with a driven large sprocket (27), the transmission spiral push-pull moving disk (24) is externally screwed with the spiral push-pull moving disk (24) with a cylindrical boss, the center of the spiral push-pull moving disk (24) is provided with a square disk with a cylindrical boss, the center boss is matched with the spiral transmission shaft (23) with the spiral transmission shaft and the upper section of the spiral transmission column is provided with a cylindrical column, each push-pull rod fixing through hole is internally provided with a push-pull rod (25), the push-pull rod (25) is a stepped rod piece with threads at two ends, the piston mud pressing plate (26) is an annular disc, the center part of the piston mud pressing plate (26) is provided with a through hole matched with the upper section of the spiral transmission shaft (23), the lower end surface of the piston mud pressing plate (26) is provided with a plurality of push-pull rod fixing threaded counter bores, the upper end of the push-pull rod (25) is rotatably arranged in the fixing threaded counter bores of the piston mud pressing plate (26), the push-pull rod fixing through holes of the push-pull rod (25) passing through the spiral push-pull moving disc (24) are fixed together by nuts and the spiral push-pull moving disc (24), the upper plate surface of the piston mud pressing plate is vertical to the central axis of the spiral transmission shaft, a speed reduction driving motor (5) is fixed on the upper plate (13) of the base (6) through a motor connecting fixing disc (9), a small sprocket (29) is fixed on the output shaft of the speed reduction driving motor (5), the small sprocket (29) is connected with a driven large driven sprocket (27) through a transmission chain, the outer die, the lower end of the outer die pipe is fixed with a control cylinder (30) and is provided with a boss (30) matched with the outer diameter of a control cylinder (30), the inner mold core (3) is a rotary body with a large upper part and a small lower part, the upper part of the rotary body is cylindrical, a square boss matched with a square concave hole in the upper end face of the spiral transmission shaft (23) is arranged on the lower end face of the inner mold core (3), a step-shaped fastening screw insertion hole (32) is formed in the upper end of the inner mold core (3), and the square boss of the inner mold core (3) is inserted into the square concave hole in the upper end face of the spiral transmission shaft (23) and is fixed with the spiral transmission shaft (23) together through a fastening screw; two reinforcing rib foot plates (33) are arranged at the middle part of the lower long side of the frame body; a backing plate is arranged below the tubular frame legs (16).

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