Vacuum tumbling machine

Abstract

The invention relates to the field of meat product pickling, and particularly discloses a vacuum tumbling machine which comprises a base, a roller used for tumbling meat products is arranged on the upper side of the base, and the roller is rotationally connected to the base through a fixed support and a lifting support; meat products to be rolled and kneaded are mixed with ingredients and then poured into the roller, the sealing cover covers the end of the roller, the clamping wheel rotates, the roller rotates along with the roller, the meat products are rolled and kneaded in the roller, the fixed support supports one end of the roller, and the lifting support lifts the other end of the roller, so that the roller swings up and down with the fixed support as the center. And after the meat products are rolled, the rear end of the roller is lifted by the lifting support, so that the inclined roller is more convenient to take out the rolled meat products, and the rolling effect of the meat products can be further improved through the arrangement of the convex strips.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of meat products pickling, in particular to a vacuum tumbling machine. BACKGROUND

[0002] The vacuum tumbling machine is the main processing equipment for food manufacturers to produce meat products and low-temperature ham, which can fully contact the protein in the tenderized raw meat with brine, accelerate the dissolution and interaction of the protein, increase the adhesion between the meat blocks, and make the meat blocks color, improve the meat tenderness and water retention, and improve the quality of the meat blocks. The drum of the traditional tumbling machine can only rotate around its axis, so the tumbling direction of the meat products is fixed, the tumbling effect is not ideal, and the meat products are not easy to take out after tumbling. SUMMARY

[0003] The purpose of the present application is to provide a vacuum tumbling machine to overcome the above-mentioned defects in the prior art.

[0004] According to the vacuum tumbling machine of the present application, the base is provided with a tumbling assembly for tumbling meat products on the upper side, and the tumbling assembly is rotatably connected to the base through a fixed support and a lifting support; The tumbling assembly comprises a drum, a sealing cover, and two clamping assemblies arranged at the front and rear ends of the outer periphery of the drum, the clamping assemblies are composed of two half-supporting structures symmetrically arranged around the axis of the drum, the half-supporting structure comprises a supporting shell, side plates are fixed on the front and rear sides of the supporting shell, two clamping wheels symmetrically arranged above and below and abutting against the outer periphery of the drum are rotatably connected between the two side plates, and connecting shafts horizontally arranged and perpendicular to the axis of the drum are fixed on the supporting shell; The fixed support comprises two fixed plates fixed on the upper end face of the base, and the two side plates at the front end of the drum are rotatably connected to the two fixed plates; The lifting support comprises two guide seats slidingly connected to the base and a semicircular lifting seat, the two side plates at the rear end of the drum are rotatably connected to the two ends of the lifting seat, two sliding blocks are fixed on the outer periphery of the lifting seat, and the two sliding blocks vertically slide in the two guide seats.

[0005] Through the above technical solution, the meat products to be tumbled and the ingredients are mixed and poured into the drum, the sealing cover is covered on the end of the drum, the clamping wheel rotates, the drum rotates, the meat products are tumbled in the drum, the fixed support supports one end of the drum, and the lifting support lifts the other end of the drum, so that the drum swings up and down around the fixed support, thereby increasing the tumbling effect of the meat products. After the tumbling of the meat products is completed, the lifting support lifts the rear end of the drum, so that the inclined drum is more convenient for taking out the tumbled meat products.

[0006] Further, the support shell is arc-shaped, two clamping wheel shafts are arranged between the two side plates and located at the upper and lower ends of the support shell respectively, the clamping wheel shafts are rotatably connected to the two side plates at the two ends respectively, one of the side plates is fixed with a motor, the clamping wheel shafts are fixed to the rotating shaft of the motor, four limiting rings are fixed on the outer periphery of the roller, and every two limiting rings are arranged on the two sides of the clamping wheel in the same clamping assembly.

[0007] Through the above technical scheme, the limiting ring is arranged to limit the clamping wheel between the two limiting rings on the corresponding side until the clamping wheel abuts against the outer periphery of the roller, so as to ensure the stability between the clamping wheel and the roller.

[0008] Further, the front and rear end faces of the clamping wheel are both fixed with cams, and the outer periphery of the cam abuts against the outer periphery of the limiting ring.

[0009] Through the above technical scheme, the cam abuts against the outer periphery of the limiting ring, so as to increase the support strength of the abutting position of the roller and the clamping wheel.

[0010] Further, one side of the side plate close to the corresponding clamping wheel is fixed with a lug plate, the outer surface of the lug plate abuts against the inner side of the support shell, two lug plates in the same half support structure are provided with a connecting plate, a plurality of through holes parallel to the axis of the roller are formed in the connecting plate, a circular hole corresponding to the through hole is formed in the side plate and the lug plate, a threaded sleeve rod penetrating through the through hole is arranged in the circular hole, one end of the threaded sleeve rod extends radially outward and abuts against the surface of one side plate, and the other end of the threaded sleeve rod is threadedly connected with a bolt, one end of the bolt away from the threaded sleeve rod extends radially outward and abuts against the surface of the other side plate.

[0011] Through the above technical scheme, the lug plate is arranged to increase the bending strength of the side plate, the connecting plate is arranged to increase the connecting strength between the two side plates, and the disassembly and assembly convenience between the side plate and the support shell is improved.

[0012] Further, a reinforcing plate is fixed between the two fixed plates, the lower end face of the reinforcing plate is fixed to the base, and the upper end face of the reinforcing plate is recessed downward to form a circular arc face.

[0013] Through the above technical scheme, the reinforcing plate is arranged to increase the support strength of the fixed plate.

[0014] Further, one side of the guide seat close to the lifting seat is provided with a guide groove, two sliding blocks slide in the two guide grooves respectively, the sliding block is threadedly connected with a screw rod, the upper and lower ends of the screw rod are rotatably connected to the inner side walls of the two guide grooves respectively, the bottom plate is fixedly arranged at the lower end of the guide seat, the rib plate is fixed between the upper end surface of the bottom plate and the side surface of the guide seat, the screw rod penetrates through the bottom plate, and the servo motor is fixedly arranged on the lower end surface of the bottom plate.

[0015] Through the technical scheme, the servo motor drives the screw rod to rotate, so that the sliding block moves up and down, and then the lifting seat moves up and down, and then the drum end close to the lifting seat swings up and down.

[0016] Further, the guide seat is provided with two roller seats on the side close to the lifting seat and the side away from the lifting seat, the roller seat is fixed on the bottom plate, the roller seat is provided with a roller groove on the side away from the bottom plate, two upper and lower symmetrical roller shafts are fixedly arranged on the side wall close to the bottom plate of the roller groove, rollers are rotatably connected to the roller shafts, two through grooves are formed in the upper end surface of the base along the rear end, and the two bottom plates are located in the two through grooves and slide in the through grooves.

[0017] Through the technical scheme, the roller shaft is arranged, so that the guide seat is easy to move on the base.

[0018] Further, the drum is fixedly provided with a flared end, the drum end close to the flared end is provided with a feeding port, the drum end close to the flared end is fixedly provided with a sealing ring, a plurality of pin seats are fixedly arranged on the edge of the sealing cover, a latch is slidably connected in the pin seat, a plurality of limiting seats are fixedly arranged on the inner side of the flared end, a limiting groove is formed in the side of the limiting seat close to the sealing cover, the latch can be embedded in the limiting groove, a connecting pipe is fixedly arranged on the side of the sealing cover away from the drum, and a one-way valve is fixedly arranged in the connecting pipe.

[0019] Through the technical scheme, the connecting pipe is arranged to be connected with the vacuum pump through the pipeline, and the one-way valve is arranged, so that the drum can be kept in a vacuum state after being pumped to a vacuum state.

[0020] Further, a plurality of convex strips evenly distributed in a circumferential direction with the axis as the center are fixedly arranged on the inner side wall of the drum, and the convex strips are spirally arranged along the drum axis direction.

[0021] Through the technical scheme, the arrangement of the convex strips can further improve the rolling and kneading effect of the meat products.

[0022] The beneficial effects of the present invention are as follows: the meat product to be tumbled is mixed with the ingredients and poured into the drum, the sealing cover is covered on the end of the drum, the clamping wheel rotates, the drum rotates accordingly, the meat product is tumbled and kneaded in the drum, the fixed support supports one end of the drum, and the lifting support lifts the other end of the drum, so that the drum swings up and down with the fixed support as the center, thereby increasing the tumbling and kneading effect of the meat product. After the tumbling of the meat product is completed, the lifting support raises the rear end of the drum, so that the tilted drum is more convenient for taking out the tumbled meat product. The setting of the convex strips can further improve the tumbling and kneading effect of the meat product. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a structural schematic diagram of the present invention; Figure 2 is a cross-sectional view of the present invention; Figure 3 This invention Figure 2 A in the middle is an enlarged schematic diagram; Figure 4 is a schematic cross-sectional view of the clamping assembly of the present invention; Figure 5 is an exploded view of the present invention; Figure 6 is an exploded view of the clamping assembly of the present invention; Figure 7 It is an exploded view of the lifting support in the present invention.

[0024] In the picture: 10. Base; 12. Through slot; 20. Roller; 201. Feed port; 21. Flaring; 211. Limit seat; 212. Limit slot; 22. Sealing cover; 221. Connecting pipe; 222. One-way valve; 223. Pin seat; 23. Limit ring; 24. Raised strip; 25. Sealing ring; 26. Latch; 30. Support housing; 31. Side plate; 311. Raised plate; 32. Motor; 33. Connecting shaft; 34, clamping wheel; 341, cam; 35, clamping wheel shaft; 36, connecting plate; 38, bolt; 39, threaded sleeve; 40, reinforcing plate; 41, fixing plate; 50, lifting seat; 51, slider; 60, guide seat; 601, guide groove; 61, roller; 62, roller seat; 620, roller groove; 64, bottom plate; 65, roller shaft; 66, screw; 67, rib. DETAILED DESCRIPTION

[0025] In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate directions or positional relationships based on the attached Figure 1The orientation or positional relationship shown is only for the purpose of simplifying the description of the present invention, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as a limitation on the present invention.

[0026] In order to make the objects and advantages of the present invention more clearly understood, the present invention is described in detail below with reference to the following embodiments. It should be understood that the following text is merely used to describe one or several specific embodiments of the present invention and does not strictly limit the scope of protection of the specific claims of the present invention. As used herein, the terms up and down and left and right are not limited to their strict geometric definitions, but include reasonable and inconsistent tolerances for machining or human errors. The specific features of the vacuum tumbling machine are described in detail below: An embodiment of the present invention: Reference Figures 1-7 The present invention provides a vacuum tumbling machine, comprising a base 10, a tumbling assembly for tumbling meat products is provided on the upper side of the base 10, and the tumbling assembly is rotatably connected to the base 10 through a fixed support and a lifting support; The tumbling assembly includes a roller 20, a sealing cover 22, and two clamping assemblies arranged at the front and rear ends of the outer periphery of the roller 20. The clamping assembly consists of two semi-support structures symmetrically arranged around the axis of the roller 20. The semi-support structure includes a support shell 30. Side plates 31 are fixed to the front and rear sides of the support shell 30. Two clamping wheels 34 symmetrically arranged up and down and abutting the outer periphery of the roller 20 are rotatably connected between the two side plates 31. A connecting shaft 33 arranged horizontally and perpendicular to the axis of the roller 20 is fixed to each support shell 30. The fixed support includes two fixed plates 41, which are fixed to the upper end surface of the base 10, and the two side plates 31 located at the front end of the roller 20 are respectively rotatably connected to the two fixed plates 41; The lifting support includes two guide seats 60 slidably connected to the base 10 and a semicircular lifting seat 50. The two side plates 31 located at the rear end of the drum 20 are respectively rotatably connected to the two ends of the lifting seat 50. Two sliders 51 are fixed on the outer periphery of the lifting seat 50. The two sliders 51 slide vertically in the two guide seats 60 respectively.

[0027] Reference Figures 4-6The support shell 30 is arc-shaped, two clamping wheel shafts 35 are arranged between the two side plates 31 and located at the upper and lower ends of the support shell 30 respectively, the two ends of the clamping wheel shaft 35 are rotatably connected to the two side plates 31 respectively, the clamping wheel 34 is rotatably connected to the outer periphery of the clamping wheel shaft 35, one of the side plates 31 is fixed with a motor 32, the clamping wheel shaft 35 is fixed to the rotating shaft of the motor 32, four limiting rings 23 are fixedly arranged on the outer periphery of the roller 20, every two limiting rings 23 are arranged on the two sides of the clamping wheel 34 in the same clamping assembly, the front and rear end faces of the clamping wheel 34 are fixedly provided with cams 341, the outer periphery of the cam 341 abuts against the outer periphery of the limiting ring 23, one side of the side plate 31 close to the corresponding clamping wheel 34 is fixedly provided with a convex plate 311, the outer surface of the convex plate 311 abuts against the inner side of the support shell 30, the two convex plates 311 in the same half support structure are provided with a connecting plate 36, a plurality of through holes parallel to the axis of the roller 20 are formed in the connecting plate 36, a circular hole corresponding to the through hole is formed in the side plate 31 and the convex plate 311, a threaded sleeve rod 39 penetrating the through hole is arranged in the circular hole, one end of the threaded sleeve rod 39 extends radially outward and abuts against the surface of one of the side plates 31, the other end of the threaded sleeve rod 39 is threadedly connected with a bolt 38, one end of the bolt 38 away from the threaded sleeve rod 39 extends radially outward and abuts against the surface of the other side plate 31.

[0028] With reference to Figure 5 The two fixed plates 41 are fixedly provided with a reinforcing plate 40, the lower end surface of the reinforcing plate 40 is fixed to the base 10, and the upper end surface of the reinforcing plate 40 is recessed downward to form a circular arc surface.

[0029] With reference to Figure 7 One side of the guide seat 60 close to the lifting seat 50 is provided with a guide groove 601, the two sliding blocks 51 slide up and down in the two guide grooves 601 respectively, a screw rod 66 is threadedly connected in the sliding block 51, the upper and lower ends of the screw rod 66 are rotatably connected to the upper and lower side walls of the two guide grooves 601 respectively, the lower end of the guide seat 60 is fixedly provided with a bottom plate 64, the rib plate 67 is fixed between the upper end surface of the bottom plate 64 and the side surface of the guide seat 60, the lower end of the screw rod 66 penetrates the bottom plate 64, the lower end surface of the bottom plate 64 is fixedly provided with a servo motor, and the lower end of the screw rod 66 is fixedly connected with the output shaft of the servo motor.

[0030] With reference to Figure 1 , Figure 5 , Figure 7The two roller seats 62 are fixed on the bottom plate 64, and the roller groove 620 is formed on the side of the roller seat 62 away from the bottom plate 64, and two upper and lower symmetrical roller shafts 65 are fixed on the side wall of the roller groove 620 close to the bottom plate 64, and the roller 61 is rotatably connected to the roller shaft 65, and the upper end surface of the base 10 is provided with two through grooves 12 penetrating along the rear end, and the two bottom plates 64 are respectively located in the two through grooves 12 and slide in the through grooves 12, and the roller shafts 65 on the upper and lower sides respectively clamp the edges of the two through grooves 12 parallel to the axis of the roller 20.

[0031] Referring to Figure 3 The roller 20 is fixed with a flared portion 21 at one end, and the end of the roller 20 close to the flared portion 21 is provided with an inlet 201, and the end of the roller 20 close to the flared portion 21 is fixed with a sealing ring 25, and the edge of the sealing cover 22 is fixed with a plurality of pin seats 223, and the pin seat 223 is slidably connected with a latch 26, and a plurality of limiting seats 211 are fixed on the inner side of the flared portion 21, and a limiting groove 212 is formed on the side of the limiting seat 211 close to the sealing cover 22, and the latch 26 can be embedded in the limiting groove 212, and a connecting pipe 221 is fixed on the side of the sealing cover 22 away from the roller 20, and a one-way valve 222 is fixed in the connecting pipe 221, and the one-way valve 222 is composed of a valve body, a valve core and a pull rod, and the pull rod is fixed with the valve core, and when the roller 20 is in a negative pressure state, the valve core is in a blocking state, and if it is necessary to restore the negative pressure in the roller 20 to a normal pressure, the pull rod is pulled, so that a gap is formed between the valve core and the valve body, so that air enters the roller 20 through the one-way valve 222.

[0032] Referring to Figure 2 A plurality of convex strips 24 are fixed on the inner side wall of the roller 20, which are uniformly distributed in a circumferential direction with the axis as the center, and the convex strips 24 are spirally arranged along the axis direction of the roller 20.

[0033] In use, the sealing cover 22 is opened, the meat products and ingredients are poured into the roller 20 through the inlet 201, and then the sealing cover 22 is closed, the edge of the sealing cover 22 abuts against the sealing ring 25, the latch 26 in the pin seat 223 is inserted into the limiting groove 212, so that the sealing cover 22 is fixedly connected with the roller 20, and then the vacuum pump is connected with the connecting pipe 221 through the pipeline, and the vacuum pump is started, so that the roller 20 is gradually pumped to a vacuum state, and then the pipeline is disconnected from the connecting pipe 221.

[0034] Then, the motor 32 is started, so that the clamping wheel shaft 35 rotates, and then the clamping wheel 34 rotates, so that the roller 20 rotates, and the convex strips 24 rotate with the rotation of the roller 20, so that the meat products are rolled and kneaded.

[0035] At the same time, the servo motor on the lower side of the base plate 64 is started, so that the screw rod 66 rotates forward for a period of time and then reverses for a period of time, so as to reciprocate, so that the slider 51 reciprocates up and down, thereby driving the one end of the roller 20 close to it to swing up and down, thereby increasing the rolling effect of the meat products, shortening the time required to reach the ideal rolling state, indirectly saving the equipment running time, saving the consumption of electric energy.

[0036] After the meat products are rolled and kneaded, the one end of the roller 20 close to the lifting seat 50 swings up to the highest position, and then the servo motor is turned off. At this time, the connecting pipe 221 is opened, so that the pressure in the roller 20 is restored to the initial pressure, and then the sealing cover 22 is opened. The inclined roller 20 facilitates the removal of the meat products in it. The design of the inclined discharge reduces the residue of the material in the roller 20, reduces the water and cleaning agent required for subsequent cleaning of the roller 20, and saves the resource consumption and cost of the cleaning link.

[0037] Those skilled in the art can clearly make various modifications to the above embodiments without departing from the overall spirit and concept of the present application. All fall within the scope of the present application. The protection scheme of the present application is subject to the claims attached to the present application.

Claims

1. A vacuum tumbling machine, comprising a base (10), characterized in that: A tumbling assembly for tumbling meat products is provided on the upper side of the base (10), and the tumbling assembly is rotatably connected to the base (10) via a fixed support and a lifting support; The rolling and kneading assembly comprises a roller (20), a sealing cover (22), and two clamping assemblies arranged at the front and rear ends of the outer periphery of the roller (20), the clamping assembly consisting of two semi-support structures symmetrically arranged with the axis of the roller (20) as the center, the semi-support structure comprising a support shell (30), the front and rear sides of the support shell (30) are both fixed with side plates (31), two clamping wheels (34) symmetrically arranged in upper and lower directions and abutting against the outer periphery of the roller (20) are rotatably connected between the two side plates (31), and a connecting shaft (33) arranged horizontally and perpendicular to the axis of the roller (20) is fixed on each of the support shells (30); The fixed support comprises two fixed plates (41), the fixed plates (41) being fixed on the upper end surface of the base (10), and the two side plates (31) located at the front end of the roller (20) being rotatably connected to the two fixed plates (41) respectively; The lifting support comprises two guide seats (60) slidably connected to the base (10) and a semicircular lifting seat (50), two side plates (31) located at the rear end of the roller (20) are rotatably connected to the two ends of the lifting seat (50), and two sliders (51) are fixed on the outer periphery of the lifting seat (50), and the two sliders (51) slide vertically in the two guide seats (60) respectively.

2. A vacuum tumbling machine according to claim 1, characterized in that: The support shell (30) is arc-shaped. Two clamping wheel shafts (35) are respectively located at the upper and lower ends of the support shell (30) between the two side plates (31). The two ends of the clamping wheel shaft (35) are respectively rotatably connected to the side plates (31) on both sides. The clamping wheel (34) is rotatably connected to the outer periphery of the clamping wheel shaft (35). A motor (32) is fixed to one of the side plates (31). The clamping wheel shaft (35) is fixed to the rotating shaft of the motor (32). Four limiting rings (23) are fixed on the outer periphery of the roller (20). Every two limiting rings (23) are respectively arranged on both sides of the clamping wheel (34) in the same clamping assembly.

3. The vacuum tumbling machine according to claim 2, characterized in that: Cams (341) are fixedly provided on the front and rear end surfaces of the clamping wheel (34), and the outer periphery of the cam (341) abuts against the outer periphery of the limiting ring (23).

4. The vacuum tumbling machine according to claim 3, characterized in that: A convex plate (311) is fixedly provided on one side of the side plate (31) close to the corresponding side clamping wheel (34), and the outer surface of the convex plate (311) abuts against the inner side surface of the support shell (30). A connecting plate (36) is provided between the two convex plates (311) in the same semi-support structure, and a plurality of through holes parallel to the axis of the roller (20) are provided on the connecting plate (36). Circular holes corresponding to the through holes are provided on the side plate (31) and the convex plate (311). A threaded sleeve (39) passes through the through hole, and one end of the threaded sleeve (39) extends radially outward and abuts against the surface of one side of the side plate (31). The other end of the threaded sleeve (39) is threadedly connected to a bolt (38), and the end of the bolt (38) away from the threaded sleeve (39) extends radially outward and abuts against the surface of the other side plate (31).

5. The vacuum tumbling machine according to claim 1, characterized in that: A reinforcing plate (40) is fixed between the two fixing plates (41), the lower end surface of the reinforcing plate (40) is fixed on the base (10), and the upper end surface of the reinforcing plate (40) is concave downward to form an arc surface.

6. The vacuum tumbling machine according to claim 1, characterized in that: A guide groove (601) is provided on one side of the guide seat (60) close to the lifting seat (50), and the two sliders (51) slide up and down in the two guide grooves (601) respectively. The inner thread of the slider (51) is connected to a screw rod (66), and the upper and lower ends of the screw rod (66) are rotatably connected to the upper and lower side walls of the two guide grooves (601) respectively. A bottom plate (64) is fixed at the lower end of the guide seat (60), and a rib plate (67) is fixed between the upper end surface of the bottom plate (64) and the side surface of the guide seat (60). The lower end of the screw rod (66) passes through the bottom plate (64), and a servo motor is fixed to the lower end surface of the bottom plate (64). The lower end of the screw rod (66) is fixedly connected to the output shaft of the servo motor.

7. The vacuum tumbling machine according to claim 6, characterized in that: The guide seat (60) is provided with two roller seats (62) on one side close to the lifting seat (50) and on the other side away from the lifting seat (50). The roller seats (62) are fixed on the bottom plate (64). The roller seats (62) are provided with roller grooves (620) on one side away from the bottom plate (64). Two roller shafts (65) symmetrical in upper and lower directions are fixed on the side wall of the roller groove (620) close to the bottom plate (64). The roller shafts (65) are rotatably connected to the rollers (61). The upper end surface of the base (10) is provided with two through grooves (12) passing through the rear end thereof. The two bottom plates (64) are respectively located in the two through grooves (12) and slide therein. The roller shafts (65) on the upper and lower sides respectively clamp the edges of the two through grooves (12) parallel to the axis of the roller (20).

8. The vacuum tumbling machine according to claim 1, characterized in that: A flare (21) is fixedly provided at one end of the roller (20), a feed port (201) is provided at one end of the roller (20) close to the flare (21), a sealing ring (25) is fixedly provided at one end of the roller (20) close to the flare (21), a plurality of pin seats (223) are fixedly provided on the edge of the sealing cover (22), a latch (26) is slidably connected in the pin seat (223), a plurality of limiting seats (211) are fixedly provided on the inner side surface of the flare (21), a limiting groove (212) is provided on a side of the limiting seat (211) close to the sealing cover (22), the latch (26) can be embedded in the limiting groove (212), a connecting pipe (221) is fixedly provided on a side of the sealing cover (22) away from the roller (20), and a one-way valve (222) is fixed in the connecting pipe (221).

9. The vacuum tumbling machine according to claim 1, characterized in that: A plurality of convex strips (24) are fixedly provided on the inner side wall of the drum (20) and are evenly distributed circumferentially with the drum axis as the center. The convex strips (24) are spirally arranged along the axial direction of the drum (20).

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