CN216175893U

CN216175893U - Stamping device of motor rotor punching sheet

Info

Publication number: CN216175893U
Application number: CN202122617622.7U
Authority: CN
Inventors: 徐艳华
Original assignee: Taicang Fuhua Special Motor Co ltd
Current assignee: Taicang Fuhua Special Motor Co ltd
Priority date: 2021-10-29
Filing date: 2021-10-29
Publication date: 2022-04-05
Anticipated expiration: 2031-10-29

Abstract

The utility model discloses a punching device for a motor rotor punching sheet, which comprises a workbench, a feeding mechanism and an ejection mechanism, wherein a punching cylinder is arranged above the workbench and connected with an upper die base, a punching head is fixed below the upper die base, a lower die base is arranged right below the punching head, a limiting groove for limiting the rotor punching sheet is arranged on the lower die base, and the ejection mechanism is arranged below the limiting groove; the automatic blank feeding device is characterized in that a feeding mechanism is arranged on one side of the workbench and comprises a fixed table, a feeding barrel and a suction arm, the feeding barrel and a fixed seat are arranged on the fixed table, blanks to be processed are arranged in the feeding barrel, and the fixed seat is provided with the suction arm which is rotatably connected with the fixed seat and can suck the blanks. According to the punching device for the motor rotor punching sheet, disclosed by the utility model, the feeding mechanism is used for automatically feeding, and the ejection mechanism is used for ejecting the rotor punching sheet out of the limiting groove, so that the material can be rapidly fed and taken, the production efficiency is improved, and the production cost is saved.

Description

Stamping device of motor rotor punching sheet

Technical Field

The utility model belongs to the technical field of motor rotor punching, and particularly relates to a punching device for a motor rotor punching sheet.

Background

The rotor of the motor is a rotating part in the motor, is a conversion device for realizing the conversion between electric energy and mechanical energy, and is an important component of the motor. The motor rotor is formed by laminating a plurality of rotor punching sheets, the rotor punching sheets are generally formed by punching through punching equipment, and the motor rotor punching sheets are produced through the punching equipment and are the most conventional and most effective production mode.

In the prior art, the rotor punching sheet is mostly fed in a manual feeding mode in the punching production process, so that the labor intensity is high, the production efficiency is low, the labor cost is high, and great danger exists in the feeding process; and because the thickness of the rotor punching sheet is thinner, after the punching is completed, a worker can not quickly and conveniently take out the punched rotor punching sheet, which is not beneficial to the high-efficiency punching operation of the rotor punching sheet.

SUMMERY OF THE UTILITY MODEL

Utility model purpose: in order to overcome the defects, the utility model aims to provide the punching device for the motor rotor punching sheet, which is simple in structure, can automatically feed materials through the feeding mechanism, can eject the punched rotor punching sheet from the limiting groove through the ejection mechanism, can quickly feed and take the materials, improves the production efficiency and saves the production cost.

The technical scheme is as follows: a stamping device for motor rotor punching sheets comprises a workbench, a top plate, guide columns, a stamping cylinder, a stamping head, a feeding mechanism and an ejection mechanism, wherein the guide columns are symmetrically arranged at the centers of two sides of the workbench, the top plate is fixedly connected above the guide columns, the stamping cylinder is fixed below the top plate, the output end of the stamping cylinder is connected with an upper die base, two ends of the upper die base are sleeved on the guide columns and are in sliding connection with the guide columns, the stamping head is fixed below the upper die base, a lower die base fixed on the workbench is arranged right below the stamping head, a limiting groove capable of limiting rotor punching sheets is arranged in the middle of the top surface of the lower die base and used for limiting the rotor punching sheets, and the displacement of the rotor punching sheets is avoided during stamping, and the stamping device can adapt to the processing of different rotor punching sheets by replacing the lower die base; an ejection mechanism arranged in the workbench is arranged below the limit, and the ejection mechanism can eject the punched rotor punching sheet out of the limit groove, so that inconvenience in material taking caused by the fact that the rotor punching sheet is located in the limit groove is avoided; workstation one side is equipped with feed mechanism, feed mechanism includes fixed station, material loading section of thick bamboo, fixing base and absorption arm, the fixed station front side is equipped with the material loading section of thick bamboo, be equipped with the rotor that remains to process in the material loading section of thick bamboo and towards the piece stock, material loading section of thick bamboo rear side is equipped with the fixing base, be equipped with the absorption arm that can absorb the stock on the fixing base, absorption arm and fixing base swivelling joint, the stock absorption in the material loading section of thick bamboo is drawn to the absorption arm, then the rotatory supreme material level of absorption arm, and the stock is loosened to the absorption arm, and the stock is put into the spacing groove, accomplishes automatic feeding to improved material loading efficiency greatly, saved artifically, improve the operational safety.

Furthermore, foretell stamping device of motor rotor towards piece, the guide pillar lower extreme is equipped with buffer gear, buffer gear includes sleeve, first spring, buffer board, the sleeve cover is established in the guide pillar outside and is fixed on the workstation, the sleeve top surface is equipped with first spring, fixedly connected with buffer board above the first spring, the buffer board top surface is equipped with the buffering cushion. When the stamping head stamps, a buffer force is provided for the upper die base, so that the vibration to the equipment is reduced, and the service life of the equipment is prolonged; the buffering cushion can further improve the buffer performance of buffer gear, reduces the damage to equipment.

Furthermore, foretell stamping device of motor rotor towards piece, the guide pillar overlaps with the upper die base junction and is equipped with the flange bush, flange bush and upper die base fixed connection, this setting can reduce the frictional resistance that the upper die base goes up and down for the lift of upper die base is more smooth and easy.

Furthermore, the punching device for the motor rotor punching sheet comprises a positioning bottom plate and a positioning rod, wherein the positioning bottom plate is provided with a plurality of cylindrical positioning rods uniformly arranged in the circumference, and the outer sides of the positioning rods are tangent to the outer edge of the blank, so that the positioning rods can position the blank, and the blank is guaranteed to be arranged in the feeding barrel in order.

Furthermore, foretell stamping device of motor rotor towards piece, location bottom plate central point puts and is equipped with the operation through-hole, operation through-hole below is equipped with the elevating system who fixes on the fixed station, the elevating system expansion end stretches into the operation through-hole and contacts with last feed cylinder bottommost stock, can jack-up the stock in the feed cylinder, is convenient for absorb the arm and absorbs.

Further, foretell stamping device of electric motor rotor towards piece, feed mechanism is still including the motor of locating the fixing base top, it includes the type of falling L rotary rod to absorb the arm, rotary rod montant lower extreme is connected with the motor to through motor and fixing base swivelling joint, be equipped with the sliding arm on the rotary rod horizontal pole, the sliding arm below is equipped with the lift cylinder, lift cylinder output is connected with the connecting plate, the connecting plate below is equipped with the sucking disc, and sucking disc quantity can be equipped with 1 or a plurality of according to stock external diameter size. During feeding, the lifting cylinder stretches out, the sucker descends, the sucker sucks the blank, then the motor drives the rotating rod to rotate, the sucker rotates to the position above the limiting groove, the sucker loosens the blank, and the blank is placed into the limiting groove.

Furthermore, according to the punching device for the motor rotor punching sheet, the moving cylinder is fixed on the outer side of the rotary rod cross rod, the output end of the moving cylinder is connected with the sliding arm, and the sliding arm is connected with the rotary rod cross rod in a sliding mode through the moving cylinder. When the distance from the feeding barrel to the sucker is different from the distance from the limiting groove to the sucker, after the sucker sucks blank from the feeding barrel, the sliding arm can be controlled to extend through the movable air cylinder, so that the sucker is above the limiting groove, the sliding arm is too long to generate interference when the material is taken, and the occupied space of the feeding mechanism is saved.

Further, foretell stamping device of motor rotor towards piece, ejection mechanism includes roof, second spring, guide arm, be equipped with the mounting groove that runs through workstation mesa and spacing groove intercommunication under the spacing groove, sliding connection has the guide arm in the mounting groove, the guide arm top is connected with the roof that stretches into the spacing inslot, the roof below is connected with the cover and establishes the second spring on the guide arm. After the punching is finished, the punching head rises, and the punched rotor punching sheet is ejected out of the limiting groove under the action of the second spring.

Further, foretell stamping device of electric motor rotor towards piece, the mounting groove is the echelonment, and from the top down is upper segment, middle section and hypomere respectively, the upper segment aperture is less than spacing groove hole diameter, the upper segment is located to the second spring, and second spring bottom surface and upper segment bottom step face butt, middle section and guide arm clearance sliding connection, the hypomere is equipped with the spout, the guide arm lower extreme be equipped with spout matched with slip table, the removal of guide arm for the accurate removal of following spacing groove the central axis direction of roof is avoided removing the aversion and is leaded to the rotor towards piece can not be smooth ejecting from the spacing inslot.

Furthermore, in the punching device for the motor rotor punching sheet, the outer edge of the bottom surface of the top plate is provided with the buffer gasket. When punching press, the cushion ring can provide the cushion effect to the roof, produces too big vibration when avoiding roof and upper segment bottom step face to contact.

The technical scheme shows that the utility model has the following beneficial effects: the punching device of the motor rotor punching sheet has the advantages of simple structure, low manufacturing cost and long service life; the punched rotor punching sheet is ejected out of the limiting groove through the ejection mechanism, so that the rotor punching sheet can be taken out quickly and conveniently; through feeding mechanism automatic feeding, can be quick material loading, get the material, improved production efficiency, saved manufacturing cost, improved the operation security.

Drawings

Fig. 1 is a schematic structural diagram of a punching device for a motor rotor punching sheet according to the present invention;

fig. 2 is a schematic side view of a feeding mechanism of a punching device for motor rotor sheets according to the present invention;

fig. 3 is a schematic structural diagram of a top view of an upper charging barrel of the punching device for the motor rotor punching sheet according to the present invention;

fig. 4 is a schematic view of a partially enlarged structure a in fig. 1 of a punching device for a motor rotor punching sheet according to the present invention;

in the figure: 10 of a workbench, 11 of a mounting groove, 111 of an upper section, 112 of a middle section, 113 of a lower section, 114 of a sliding groove, 12 of a top plate, 13 of a guide pillar, 14 of a stamping cylinder, 15 of a stamping head, 16 of an upper die holder, 17 of a lower die holder, 171 of a limiting groove, 18 of rotor sheets and 19 of a flange bushing;

20 feeding mechanisms, 21 fixing tables, 22 feeding barrels, 221 positioning bottom plates, 222 positioning rods, 223 operation through holes, 23 fixing seats, 24 suction arms, 241 rotating rods, 242 sliding arms, 243 lifting cylinders, 244 connecting plates, 245 suckers, 246 moving cylinders, 25 blanks, 26 lifting mechanisms and 27 motors;

30 ejection mechanisms, 31 top plates, 32 second springs, 33 guide rods and 34 buffer washers;

40 buffer mechanism, 41 sleeve, 42 first spring, 43 buffer plate.

Detailed Description

The utility model is further elucidated with reference to the drawings and the embodiments.

Reference will now be made in detail to embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to the same or similar elements or elements having the same or similar function throughout. The embodiments described below with reference to the drawings are illustrative and intended to be illustrative of the utility model and are not to be construed as limiting the utility model.

In the description of the present invention, it is to be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "clockwise", "counterclockwise", and the like, indicate orientations and positional relationships based on those shown in the drawings, and are used only for convenience of description and simplicity of description, and do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, are not to be considered as limiting the present invention.

Furthermore, the terms "first", "second" and "first" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of the present invention, unless otherwise specified, "a plurality" means two or more unless explicitly defined otherwise.

In the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," "secured," and the like are to be construed broadly and can, for example, be fixedly connected, detachably connected, or integrally connected; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood by those skilled in the art according to specific situations.

In the present invention, unless otherwise expressly stated or limited, "above" or "below" a first feature means that the first and second features are in direct contact, or that the first and second features are not in direct contact but are in contact with each other via another feature therebetween. Also, the first feature being "on," "above" and "over" the second feature includes the first feature being directly on and obliquely above the second feature, or merely indicating that the first feature is at a higher level than the second feature. A first feature being "under," "below," and "beneath" a second feature includes the first feature being directly under and obliquely below the second feature, or simply meaning that the first feature is at a lesser elevation than the second feature.

Example 1

As shown in fig. 1-4, the punching device for punching a rotor sheet of an electric motor according to the present invention includes a working table 10, a top plate 12, a guide pillar 13, a punching cylinder 14, a punching head 15, a feeding mechanism 20, and an ejection mechanism 30, guide posts 13 are symmetrically arranged at the centers of both sides of the workbench 10, a top plate 12 is fixedly connected above the guide posts 13, a stamping cylinder 14 is fixed below the top plate 12, the output end of the stamping cylinder 14 is connected with an upper die holder 16, two ends of the upper die holder 16 are sleeved on the guide post 13, and is connected with the guide post 13 in a sliding way, a stamping head 15 is fixed under the upper die holder 16, a lower die holder 17 fixed on the workbench 10 is arranged under the stamping head 15, a limit groove 171 is arranged at the middle position of the top surface of the lower die holder 17, the rotor punching sheet 18 can be limited, the rotor punching sheet 18 is prevented from shifting during punching, and the lower die base 17 is replaced, so that the punching die is suitable for processing different rotor punching sheets.

The ejection mechanism 30 arranged in the workbench 10 is arranged below the limiting groove 171, the ejection mechanism 30 can eject the punched rotor sheet 18 out of the limiting groove 171, and inconvenience in material taking caused by the fact that the rotor sheet is located in the limiting groove 171 is avoided.

A feeding mechanism 20 is arranged on one side of the workbench 10, the feeding mechanism 20 comprises a fixed table 21, a feeding cylinder 22, a fixed seat 23 and a suction arm 24, the feeding cylinder 22 is arranged on the front side of the fixed table 21, a rotor punching sheet blank 25 to be processed is arranged in the feeding cylinder 22, the fixed seat 23 is arranged on the rear side of the feeding cylinder 22, and the suction arm 24 capable of sucking the blank is arranged on the fixed seat 23; feed mechanism 20 is still including locating the motor 27 above fixing base 23, it includes the type of falling L rotary rod 241 to absorb arm 24, rotary rod 241 montant lower extreme is connected with motor 27 to through motor 27 and fixing base 23 swivelling joint, be equipped with slide arm 242 on the rotary rod 241 horizontal pole, slide arm 242 below is equipped with lift cylinder 243, lift cylinder 243 output is connected with connecting plate 244, the connecting plate 244 below is equipped with sucking disc 245. During the material loading, lift cylinder 243 stretches out, and sucking disc 245 descends, and sucking disc 245 absorbs the stock 25 with in the feed cylinder 22, and then motor 27 drive rotary rod 241 is rotatory, and sucking disc 245 rotates to spacing groove 171 top, and sucking disc 245 loosens stock 25, puts into spacing groove 171 with stock 25, accomplishes automatic feeding to improved material loading efficiency greatly, saved the manual work, improved the operational safety.

Example 2

As shown in fig. 1-2, a moving cylinder 246 is fixed outside the cross bar of the rotating rod 241, the output end of the moving cylinder 246 is connected with a sliding arm 242, and the sliding arm 242 is slidably connected with the cross bar of the rotating rod 241 through the moving cylinder 246. When the distance between the upper material cylinder 22 and the suction cup 245 is different from the distance between the limiting groove 171 and the suction cup 245, after the suction cup 245 sucks the blank 25 from the upper material cylinder 22, the sliding arm 242 can be controlled to extend by the moving cylinder 246, so that the suction cup 245 moves to the upper side of the limiting groove 171, interference caused by the overlong sliding arm 242 is avoided, and the occupied space of the feeding mechanism 20 is saved.

As shown in fig. 1, a buffer mechanism 40 is disposed at the lower end of the guide post 13, the buffer mechanism 40 includes a sleeve 41, a first spring 42, and a buffer plate 43, the sleeve 41 is sleeved outside the guide post 13 and fixed on the worktable 10, the first spring 42 is disposed on the top surface of the sleeve 41, the buffer plate 43 is fixedly connected above the first spring 42, and a buffer rubber pad is disposed on the top surface of the buffer plate 43. When the stamping head 15 stamps, the buffer mechanism 40 gives a buffer force to the upper die holder 16, so that the vibration to the equipment is reduced, and the service life of the equipment is prolonged; the buffering cushion can further improve the buffering performance of the buffering mechanism 40 and reduce the damage to equipment.

The joint of the guide post 13 and the upper die holder 16 is sleeved with a flange bushing 19, and the flange bushing 19 is fixedly connected with the upper die holder 16.

As shown in fig. 1-3, the charging barrel 22 includes a positioning bottom plate 221 and positioning rods 222, the positioning bottom plate 221 is provided with a plurality of cylindrical positioning rods 222 uniformly arranged around the circumference, and the outer sides of the positioning rods 222 are tangent to the outer edge of the blank 25, so that the positioning rods 222 perform a positioning function on the blank 25, thereby ensuring that the blanks 25 are arranged in the charging barrel 22.

The central position of the positioning bottom plate 221 is provided with an operation through hole 223, a lifting mechanism 26 fixed on the fixed platform 21 is arranged below the operation through hole 223, the movable end of the lifting mechanism 26 extends into the operation through hole 223 and contacts with the bottommost blank 25 of the upper charging barrel 22, the lifting mechanism 26 can jack up the blank 25 in the upper charging barrel 22, and the blank is conveniently sucked by the suction arm 24.

As shown in fig. 1 and 4, the ejection mechanism 30 includes a top plate 31, a second spring 32, and a guide rod 33, a mounting groove 11 penetrating through the top surface of the worktable 10 and communicating with the limiting groove 171 is provided under the limiting groove 171, the guide rod 33 is slidably connected in the mounting groove 11, the top plate 31 extending into the limiting groove 171 is connected above the guide rod 33, and the second spring 32 sleeved on the guide rod 33 is connected below the top plate 31. After the punching is completed, the punching head 15 is lifted, and the punched rotor punching sheet 18 is ejected out of the limit groove 171 under the action of the second spring 32.

Mounting groove 11 is the echelonment, and from the top down is upper segment 111, middle section 112 and hypomere 113 respectively, upper segment 111 aperture is less than spacing groove 171 aperture, upper segment 111 is located to second spring 32, and second spring 32 bottom surface and the 111 bottom step face butt of upper segment, middle section 112 and guide arm 33 sliding connection, hypomere 113 is equipped with spout 114, guide arm 33 lower extreme be equipped with spout 114 matched with slip table, the removal of guide arm 33 for roof 31 is accurate to remove along spacing groove 171 the central axis direction, avoids removing the aversion and leads to rotor punching sheet 18 can not be smooth ejecting from spacing groove 171.

The outer edge of the bottom surface of the top plate 31 is provided with a buffer gasket 34. The cushion washer 34 can provide a cushion force to the top plate 31 during punching, and avoid excessive vibration when the top plate 31 contacts with the bottom step surface of the upper section 111.

The foregoing is only a preferred embodiment of the present invention, and it should be noted that modifications can be made by those skilled in the art without departing from the principle of the present invention, and these modifications should also be construed as the protection scope of the present invention.

Claims

1. The utility model provides a stamping device of motor rotor punching which characterized in that: comprises a workbench (10), a top plate (12), a guide post (13), a stamping cylinder (14), a stamping head (15), a feeding mechanism (20) and an ejection mechanism (30), guide posts (13) are symmetrically arranged at the centers of two sides of the workbench (10), a top plate (12) is fixedly connected above the guide posts (13), a stamping cylinder (14) is fixed below the top plate (12), the output end of the stamping cylinder (14) is connected with an upper die holder (16), two ends of the upper die holder (16) are sleeved on the guide post (13), and is connected with the guide post (13) in a sliding way, a stamping head (15) is fixed below the upper die holder (16), a lower die seat (17) fixed on the workbench (10) is arranged under the stamping head (15), a limiting groove (171) capable of limiting the rotor punching sheet (18) is arranged in the middle of the top surface of the lower die seat (17), an ejection mechanism (30) arranged in the workbench (10) is arranged below the limiting groove (171); workstation (10) one side is equipped with feed mechanism (20), feed mechanism (20) include fixed station (21), go up feed cylinder (22), fixing base (23) and absorb arm (24), fixed station (21) front side is equipped with feed cylinder (22), it is equipped with rotor punching sheet stock (25) that remain to process to go up to be equipped with in feed cylinder (22), it is equipped with fixing base (23) to go up feed cylinder (22) rear side, be equipped with on fixing base (23) and absorb arm (24) that can absorb stock (25), absorb arm (24) and fixing base (23) swivelling joint.

2. The punching device of the motor rotor punching sheet as claimed in claim 1, characterized in that: the lower end of the guide pillar (13) is provided with a buffer mechanism (40), the buffer mechanism (40) comprises a sleeve (41), a first spring (42) and a buffer plate (43), the sleeve (41) is sleeved on the outer side of the guide pillar (13) and fixed on the workbench (10), the top surface of the sleeve (41) is provided with the first spring (42), the buffer plate (43) is fixedly connected to the upper side of the first spring (42), and the top surface of the buffer plate (43) is provided with a buffer rubber mat.

3. The punching device of the motor rotor punching sheet as claimed in claim 2, characterized in that: a flange bushing (19) is sleeved at the joint of the guide post (13) and the upper die base (16), and the flange bushing (19) is fixedly connected with the upper die base (16).

4. The punching device of the motor rotor punching sheet as claimed in claim 1, characterized in that: the feeding barrel (22) comprises a positioning bottom plate (221) and positioning rods (222), a plurality of cylindrical positioning rods (222) which are uniformly arranged circumferentially are arranged on the periphery of the positioning bottom plate (221), and the outer sides of the positioning rods (222) are tangent to the outer edge of the blank (25).

5. The punching device of the motor rotor punching sheet as claimed in claim 4, characterized in that: the positioning bottom plate (221) is provided with an operation through hole (223) in the center, a lifting mechanism (26) fixed on the fixing platform (21) is arranged below the operation through hole (223), and the lifting mechanism (26) extends into the operation through hole (223) and is in contact with the bottommost blank (25) of the upper charging barrel (22).

6. The punching device of the motor rotor punching sheet as claimed in claim 1, characterized in that: feed mechanism (20) are still including motor (27) of locating fixing base (23) top, absorb arm (24) including falling L type rotary rod (241), rotary rod (241) montant lower extreme is connected with motor (27) to through motor (27) and fixing base (23) swivelling joint, be equipped with slide arm (242) on rotary rod (241) the horizontal pole, slide arm (242) below is equipped with lift cylinder (243), lift cylinder (243) output is connected with connecting plate (244), the connecting plate (244) below is equipped with sucking disc (245).

7. The punching device of the motor rotor punching sheet as claimed in claim 6, characterized in that: a moving air cylinder (246) is fixed on the outer side of the cross rod of the rotating rod (241), the output end of the moving air cylinder (246) is connected with a sliding arm (242), and the sliding arm (242) is connected with the cross rod of the rotating rod (241) in a sliding mode through the moving air cylinder (246).

8. The punching device of the motor rotor punching sheet as claimed in claim 1, characterized in that: ejection mechanism (30) include roof (31), second spring (32), guide arm (33), be equipped with under spacing groove (171) and run through workstation (10) mesa and with mounting groove (11) of spacing groove (171) intercommunication, sliding connection has guide arm (33) in mounting groove (11), guide arm (33) top is connected with roof (31) that stretch into in spacing groove (171), roof (31) below is connected with second spring (32) that the cover was established on guide arm (33).

9. The punching device of the motor rotor punching sheet as recited in claim 8, characterized in that: mounting groove (11) are the echelonment, are upper segment (111), middle section (112) and hypomere (113) respectively from the top down, upper segment (111) aperture is less than spacing groove (171) aperture, upper segment (111) are located in second spring (32), and second spring (32) bottom surface and upper segment (111) bottom step face butt, middle section (112) and guide arm (33) sliding connection, hypomere (113) are equipped with spout (114), guide arm (33) lower extreme is equipped with the slip table with spout (114) matched with.

10. The punching device of the motor rotor punching sheet as claimed in claim 9, characterized in that: and a buffer gasket (34) is arranged on the outer edge of the bottom surface of the top plate (31).