CN113932606B

CN113932606B - Heating device of vacuum smelting furnace for producing high-resistance electric heating alloy wires

Info

Publication number: CN113932606B
Application number: CN202111196173.1A
Authority: CN
Inventors: 叶明华
Original assignee: Changshu Electric Heating Alloy Material Factory Co ltd
Current assignee: Changshu Electric Heating Alloy Material Factory Co ltd
Priority date: 2021-10-14
Filing date: 2021-10-14
Publication date: 2022-08-05
Anticipated expiration: 2041-10-14
Also published as: CN113932606A

Abstract

The invention discloses a heating device of a vacuum smelting furnace for producing high-resistance electrothermal alloy wires, which relates to the field of alloy processing and manufacturing equipment. The fixing device provided by the invention can automatically center and fix the smelting furnace placed on the placing plate; the heat preservation device can adapt to vacuum melting furnaces of different specifications, and can cancel a heat preservation system when cooling, so that enough space is reserved for cooling.

Description

Heating device of vacuum smelting furnace for producing high-resistance electric heating alloy wires

Technical Field

The invention relates to the field of alloy processing and manufacturing equipment, in particular to a heating device of a vacuum smelting furnace for producing high-resistance electric heating alloy wires.

Background

In the production of high-resistance electrothermal alloy wires, a vacuum melting furnace is generally used for heating and melting raw materials, in the production flow, because partial steps need heat preservation treatment, the heating temperature and the heat preservation time of the vacuum melting furnace need to be strictly controlled, so that the requirement on heating equipment is high, in the prior art, only heating equipment is generally used, so that the heat preservation function is neglected, and therefore, a heating device of the vacuum melting furnace for producing the high-resistance electrothermal alloy wires is needed. Chinese patent publication No. CN103575094A discloses a convection heating device for a vacuum furnace, which adopts the following technical scheme: the heat-insulation cage with the double-layer structure mainly comprises an outer layer and an inner layer, wherein a convection channel is formed by a gap between the inner layer and the outer layer, and a plurality of ventilation holes are formed in the periphery of the inner layer; the motor is arranged on one side of the heat-insulating cage with the double-layer structure, the fan blade at the tail end of the motor shaft is arranged in the convection channel between the inner layer and the outer layer, a hole is formed in the end face, close to the fan blade, of one side of the inner layer, the hole penetrates through the wind convection channel and the inner layer cavity, and the workpiece is arranged in the inner layer cavity. Through designing the thermal-insulated cage that keeps warm for bilayer structure, the work piece is arranged in the inlayer cavity, utilizes the motor that the thermal-insulated cage side that keeps warm set up to drive the terminal fan blade of starter shaft, utilizes wind convection current passageway, ventilation hole and the hole that is close to on the inlayer of fan blade one side to form the wind channel, and the heating operation of work piece is accomplished to the efficient. The device can effectively heat, is provided with a heat-preservation and heat-insulation cage, can preserve heat of a heated workpiece, but cannot adjust heat preservation and cannot control a heat-preservation space to adapt to different objects to be heated.

Disclosure of Invention

The invention aims to solve the technical problem of providing a device capable of automatically heating a vacuum melting furnace aiming at the defects in the prior art, and overcomes the defects that the heat preservation space cannot be adjusted and enough space is not available for heat dissipation in the prior art.

The technical scheme adopted by the invention for solving the technical problems is as follows: the heating device comprises a rack, a fixing device, a heating device and a heat preservation device, wherein the fixing device, the heating device and the heat preservation device are arranged on the rack, the fixing device is connected with the heating device, the heat preservation device comprises a heat preservation control power source fixedly arranged on the rack, the heat preservation control power source is connected with a heat preservation control assembly through a gear set, the heat preservation control assembly comprises a control lead screw connected with the gear set, the control lead screw is arranged on the rack and matched with a sliding frame, the sliding frame is arranged on the rack, a tightening rack is arranged on the sliding frame, the tightening rack is matched with a tightening gear I, the tightening gear I is arranged on the rack, the tightening gear I is connected with a tightening gear II, the tightening gear II is matched with a tightening gear III, the three tightening gears are arranged on the tightening rotating rods, the tightening rotating rods are arranged on the rack, tightening rope rollers are further arranged on the tightening rotating rods, tightening ropes are arranged on the tightening rope rollers, the end portions of the tightening ropes are connected with fixing strips, the fixing strips are connected with sliding rods, the sliding rods are arranged on fixed sliding plates, the fixed sliding plates are arranged on the rack, heat-insulating cloth tightening boxes are arranged on the sliding frames, heat-insulating cloth rotating rollers I and heat-insulating cloth rotating rollers II are arranged in the heat-insulating cloth tightening boxes, and the heat-insulating cloth rotating rollers I and the heat-insulating cloth rotating rollers II are connected with heat-insulating cloth.

Furthermore, the gear set comprises a first control gear connected with a heat-preservation control power source, the first control gear is matched with a second control gear, the second control gear is arranged on the rack and connected with a first control bevel gear, the first control bevel gear is matched with the second control bevel gear, and the second control bevel gear is arranged at one end of a control screw rod.

Furthermore, the heat-preservation control assembly is uniformly provided with at least four groups along the circumference of the rack, and the connection relations between the same parts are the same.

Furthermore, every group the heat preservation cloth in the heat preservation control subassembly heat preservation cloth tightens up the box changes two upsides of roller one and heat preservation cloth and changes two fixedly connected with synchronizing gear, and two synchronizing gear meshing, two the synchronizing gear downside all is provided with the torsional spring.

Furthermore, the first heat-preservation cloth roller of one group of the heat-preservation control assemblies is connected with one end of the heat-preservation cloth, the other end of the heat-preservation cloth is arranged on the second heat-preservation cloth roller of the other group of the heat-preservation control assemblies adjacent to the one group of the heat-preservation control assemblies, and the middle part of the heat-preservation cloth is fixed on the fixing strip of the one group of the heat-preservation control assemblies.

Further, fixing device is including setting up the lift cylinder in the frame, the lift cylinder with place the dish and be connected, it is provided with a plurality of balls to place to coil, evenly is provided with at least three splint along placing a set circumference.

Furthermore, the heating device comprises a heating fixing plate arranged on the frame, a top platform is arranged in the center of the heating fixing plate, a square hole is formed in the top platform, a heating resistance wire is arranged on the heating fixing plate, a cooling fan is arranged on the outer side of the heating fixing plate, a cooling inner toothed ring is arranged on the cooling fan, the cooling inner toothed ring is matched with a cooling gear, the cooling gear is connected with a cooling power source, and the cooling power source is arranged on the heating fixing plate.

Further, all splint are equallyd divide and are do not connected with a splint connecting plate, be provided with the splint rack on the splint connecting plate, all the splint rack all cooperates with splint gear, splint gear sets up in the splint change, the splint change sets up and is placing a set downside central point, splint change inboard is provided with the screw thread, the inboard screw thread of splint change cooperates with screw thread section of thick bamboo outside screw thread, screw thread section of thick bamboo and location square column sliding fit, location square column sets up and is placing a set downside central point.

Compared with the prior art, the invention has the beneficial effects that: (1) the fixing device provided by the invention can automatically center and fix the smelting furnace placed on the placing plate, so that the automation degree of the equipment is increased; (2) the cooling fan arranged on the heating device can quickly cool the equipment when the equipment is not kept warm; (3) the heat preservation device provided by the invention can adapt to vacuum melting furnaces of different specifications, and can cancel a heat preservation system during cooling to reserve enough space for cooling.

Drawings

Fig. 1 is a schematic view of the overall structure of the present invention.

FIG. 2 is a schematic top view of the tray of the present invention.

Fig. 3 is a schematic bottom view of the tray of the present invention.

Fig. 4 is an enlarged view of a structure shown in fig. 3.

FIG. 5 is a schematic top view of the temperature raising device of the present invention.

FIG. 6 is a schematic bottom view of the temperature raising device of the present invention.

FIG. 7 is a partially enlarged view of the heat retention device of the present invention.

Fig. 8 is an enlarged view of the structure at B in fig. 7.

FIG. 9 is a schematic structural diagram of a first thermal insulation apparatus according to the present invention.

FIG. 10 is a schematic structural diagram of a second thermal insulation apparatus according to the present invention.

Description of the drawings: 1-a frame; 2-a fixing device; 3-a temperature rising device; 4-a heat preservation device; 5-lifting cylinder; 6-placing a tray; 7-a ball bearing; 8-clamping plate; 9-a splint connecting plate; 10-a first limit spring; 11-a cleat rack; 12-a jaw gear; 13-rotating the clamping plate; 14-a threaded cylinder; 15-positioning square column; 16-a top stage; 17-heating the fixed plate; 18-heating resistance wires; 19-cooling fan; 20-cooling power source; 21-a cooling gear; 22-cooling inner toothed ring; 23-heat preservation control power source; 24-control gear one; 25-control gear two; 26-control the bevel gear I; 27-control the bevel gear II; 28-control lead screw; 29-control guide bar; 30-a carriage; 31-tightening the rack; 32-a second limit spring; 33-take-up gear one; 34-take-up gear two; 35-tightening gear three; 36-tightening the rotating rod; 37-tightening rope rollers; 38-tightening the rope; 39-fixed slide plate; 40-fixing strips; 41-a slide bar; 42-heat preservation cloth; 43-a first heat-preservation cloth roller; 44-heat preservation cloth roller II; 45-synchronizing gear; 46-torsion spring; 47-tightening box of heat preservation cloth.

Detailed Description

In the following description of the present invention, it is to be noted that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", and the like indicate orientations or positional relationships based on those shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention.

In the following description of the present invention, it is to be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "disposed," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; the connection may be direct or indirect via an intermediate medium, and the connection may be internal to the two components. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

The invention will be further described with reference to the drawings and illustrative embodiments, which are provided herein to illustrate and not to limit the invention. Wherein like reference numerals refer to like parts throughout. In addition, if a detailed description of the known art is not necessary to show the features of the present invention, it is omitted.

Example (b): referring to fig. 1-10, a heating device of a vacuum melting furnace for producing high resistance electrothermal alloy wires is shown, wherein a frame 1 is provided with a fixing device 2, a heating device 3 and a heat preservation device 4, and the fixing device 2 is connected with the heating device 3.

Referring to the fixing device 2 shown in fig. 1-4, wherein a lifting cylinder 5 is fixedly arranged on a frame 1, a placing plate 6 is fixedly arranged on the lifting cylinder 5, a plurality of balls 7 are arranged on the placing plate 6 in a rolling manner, four clamping plates 8 are arranged along the circumference of the placing plate 6 in a sliding manner, all the clamping plates 8 pass through the placing plate 6 and are arranged on the placing plate 6, the lower sides of all the clamping plates 8 are fixedly connected with a clamping plate connecting plate 9 respectively, all the clamping plate connecting plates 9 are slidably connected with the placing plate 6 through a limiting spring I10 respectively, a clamping plate rack 11 is fixedly arranged on the clamping plate connecting plate 9, all the clamping plate racks 11 are in gear-rack fit with a clamping plate gear 12, the clamping plate gear 12 is fixedly arranged on the outer side of a clamping plate rotating ring 13, the clamping plate rotating ring 13 is rotatably arranged at the central position of the lower side of the placing plate 6, threads are arranged on the inner side of the clamping plate rotating ring 13, the threads on the inner side of the clamping plate rotating ring 13 are in thread fit with the threads on the outer side of a thread cylinder 14, a square hole is formed in the threaded cylinder 14 and is in sliding fit with the positioning square column 15, and the positioning square column 15 is fixedly arranged at the center of the lower side of the placing disc 6.

Referring to fig. 1, fig. 3 and fig. 5-fig. 6, a heating fixing plate 17 is fixedly disposed on a rack 1, a top table 16 is fixedly disposed at a central position of the heating fixing plate 17, a square hole matched with a positioning square column 15 is disposed on the top table 16, a heating resistance wire 18 is fixedly disposed on the heating fixing plate 17, a cooling fan 19 is rotatably disposed outside the heating fixing plate 17, a cooling inner ring gear 22 is fixedly disposed at a lower side of the cooling fan 19, the cooling inner ring gear 22 is in gear fit with a cooling gear 21, the cooling gear 21 is fixedly connected with a cooling power source 20, the cooling power source 20 is fixedly disposed at a lower side of the heating fixing plate 17, and the heating fixing plate 17 is located right below a placing tray 6.

Referring to fig. 1 and fig. 7-10, a heat preservation apparatus 4 is shown, wherein a heat preservation control power source 23 is fixedly disposed on a frame 1, the heat preservation control power source 23 is fixedly connected with a first control gear 24, the first control gear 24 is in gear fit with a second control gear 25, the second control gear 25 is rotatably disposed on the frame 1, the second control gear 25 is fixedly connected with a first control bevel gear 26, the first control bevel gear 26 is in gear fit with a second control bevel gear 27, the second control bevel gear 27 is fixedly disposed at one end of a control screw 28, the control screw 28 is rotatably disposed on the frame 1, a control guide 29 is fixedly disposed on the frame 1, a carriage 30 is in threaded fit with the control screw 28, the carriage 30 is in sliding fit with the control guide 29, a tightening rack 31 is fixedly disposed on the carriage 30, the tightening rack 31 is connected with the frame 1 through a second limit spring 32, the tightening rack 31 is in gear-rack fit with a first tightening gear 33, the first tightening gear 33 is rotatably arranged on the rack 1, the first tightening gear 33 is fixedly connected with the second tightening gear 34, the second tightening gear 34 is in gear fit with the third tightening gear 35, the third tightening gear 35 is fixedly arranged on a tightening rotating rod 36, the tightening rotating rod 36 is rotatably arranged on the rack 1, a tightening rope roller 37 is further fixedly arranged on the tightening rotating rod 36, a tightening rope 38 is wound on the tightening rope roller 37, the end part of the tightening rope 38 is fixedly connected with a fixing strip 40, the fixing strip 40 is fixedly connected with a sliding rod 41, the sliding rod 41 is slidably arranged on a fixed sliding plate 39, the fixed sliding plate 39 is fixedly arranged on the rack 1, a heat-insulating cloth tightening box 47 is fixedly arranged on the sliding frame 30, the heat-insulating cloth tightening box 47 is internally and rotatably provided with a heat-insulating cloth rotating roller I43 and a heat-insulating cloth rotating roller II 44, a control gear II 25, a control bevel gear I26, a control bevel gear II 27, a control lead screw 28 and a control guide rod 29, The sliding frame 30, the tightening rack 31, the second limit spring 32, the first tightening gear 33, the second tightening gear 34, the third tightening gear 35, the tightening rotating rod 36, the tightening rope roller 37, the tightening rope 38, the fixed sliding plate 39, the fixed strip 40, the sliding rod 41, the first insulating cloth rotating roller 43, the second insulating cloth rotating roller 44 and the insulating cloth tightening box 47 form a group of insulating control components, four groups of insulating control components are uniformly arranged along the circumference of the frame 1, the connection relationship among the same parts is the same, the upper sides of the first insulating cloth rotating roller 43 and the second insulating cloth rotating roller 44 in the insulating cloth tightening box 47 in each group of insulating control components are fixedly connected with synchronous gears 45, the two synchronous gears 45 are meshed, the lower sides of the two synchronous gears 45 are respectively provided with a torsion spring 46, one end of the insulating cloth 42 is arranged on the first insulating cloth rotating roller 43 of one group of insulating control components, the other end of the insulating cloth 42 is arranged on the second insulating cloth rotating roller 44 in the other group of insulating control components adjacent to one group of insulating components, the middle part of the heat insulation cloth 42 is fixed on the fixing strip 40 of one group of the heat insulation control components.

The working principle of the invention is as follows: during operation, a vacuum melting furnace to be heated is placed on the placing plate 6, the vacuum melting furnace can freely slide due to the balls 7 arranged on the placing plate 6, then the lifting cylinder 5 drives the placing plate 6 to descend, when the placing plate 6 is in contact with the heating fixing plate 17, the positioning square column 15 on the placing plate 6 is matched with the square hole on the top platform 16, the placing plate 6 continues to descend, the top platform 16 is in contact with the threaded cylinder 14 and pushes the threaded cylinder 14 to slide upwards along the positioning square column 15, due to the fact that threads on the threaded cylinder 14 are matched with the threads on the clamping plate rotating ring 13, the threaded cylinder 14 can drive the clamping plate rotating ring 13 to rotate while moving upwards, the clamping plate rotating ring 13 drives the clamping plate gear 12 to rotate, the clamping plate gear 12 can drive the four clamping plate connecting plates 9 to move, the clamping plate 9 drives the clamping plate 8 to move to automatically center and fix the vacuum melting furnace, and at the moment, the vacuum melting furnace is heated through the heating resistance wire 18, if heat preservation is needed after heating, the heat preservation control power source 23 drives the control gear I24 to rotate, the control gear I24 rotates through matching with the control gear II 25, the control gear II 25 drives the control bevel gear I26 to rotate, the control bevel gear I26 rotates through matching with the control bevel gear II 27 to drive the control bevel gear II 27 to rotate, the control bevel gear II 27 drives the control screw 28 to rotate, the control screw 28 drives the carriage 30 to move inwards along the control guide rod 29, meanwhile, the tightening rack 31 is matched with the tightening gear I33, the tightening gear II 34 drives the tightening gear III 35 to rotate, the tightening gear III 35 drives the tightening rotating rod 36 to rotate, the tightening rotating rod 36 drives the tightening rope roller 37 to rotate, the tightening rope roller 37 loosens the tightening rope 38 to enable the tightening rope 38 not to tighten the fixing strip 40 any more, the carriage 30 moves inwards and simultaneously drives the heat preservation cloth 42 to move inwards, two sides of the heat preservation cloth 42 are respectively arranged on the heat preservation cloth rotating roller I43 and the heat preservation cloth rotating roller II 44, the first heat-preservation cloth roller 43 and the second heat-preservation cloth roller 44 automatically rotate to tighten the heat-preservation cloth 42 under the action of the torsion spring 46, the synchronous gear 45 ensures that the first heat-preservation cloth roller 43 and the second heat-preservation cloth roller 44 rotate in the same number of turns, at the moment, the heat-preservation cloth 42 can be tightly attached to a vacuum smelting furnace for heat preservation, and can be suitable for smelting furnaces of different models, if the temperature needs to be reduced, the heat preservation control power source 23 carries out reverse drive, at the moment, the first heat preservation cloth roller 43 and the second heat preservation cloth roller 44 automatically rotate to loosen the heat preservation cloth 42 under the action of the torsion spring 46, and the tightening rope roller 37 drives the tightening rope 38 to tighten, the tightening rope 38 pulls the fixing strip 40, and will keep warm cloth 42 tensile expansion, can reserve the biggest space at this moment and cool down to the smelting furnace, if need rapid cooling, cooling power source 20 will drive cooling gear 21 and rotate, and cooling gear 21 drives cooling inner gear ring 22 and rotates, and cooling inner gear ring 22 drives cooling fan 19 and rotates and cool down.

It should be understood that the above embodiments are only used for illustrating the technical solutions of the present invention, and not for limiting the same, and those skilled in the art can modify the technical solutions described in the above embodiments, or make equivalent substitutions for some technical features; and all such modifications and alterations are intended to fall within the scope of the appended claims.

Claims

1. The utility model provides a production high resistance electric heating is heating device of vacuum melting furnace for alloy silk, includes frame (1), fixing device (2), rising temperature device (3) and heat preservation device (4) set up on frame (1), fixing device (2) are connected its characterized in that with rising temperature device (3):

the heat preservation device (4) comprises a heat preservation control power source (23) fixedly arranged on the rack (1), and the heat preservation control power source (23) is connected with the heat preservation control assembly through a gear set;

the heat preservation control assembly comprises a control lead screw (28) connected with a gear set, the control lead screw (28) is arranged on the rack (1) and matched with a sliding frame (30), the sliding frame (30) is arranged on the rack (1), a tightening rack (31) is arranged on the sliding frame (30), the tightening rack (31) is matched with a first tightening gear (33), the first tightening gear (33) is arranged on the rack (1), the first tightening gear (33) is connected with a second tightening gear (34), the second tightening gear (34) is matched with a third tightening gear (35), the third tightening gear (35) is arranged on a tightening rotating rod (36), the tightening rotating rod (36) is arranged on the rack (1), a tightening rope roller (37) is further arranged on the tightening rotating rod (36), and a tightening rope (38) is arranged on the tightening rope roller (37), the tightening rope (38) end is connected with a fixing strip (40), the fixing strip (40) is connected with a sliding rod (41), the sliding rod (41) is arranged on a fixed sliding plate (39), the fixed sliding plate (39) is arranged on the rack (1), a heat-preservation cloth tightening box (47) is arranged on the sliding frame (30), a heat-preservation cloth rotating roller I (43) and a heat-preservation cloth rotating roller II (44) are arranged in the heat-preservation cloth tightening box (47), and the heat-preservation cloth rotating roller I (43) and the heat-preservation cloth rotating roller II (44) are connected with the heat-preservation cloth (42).

2. The heating apparatus of a vacuum melting furnace for producing a high electric resistance electrothermal alloy wire according to claim 1, characterized in that: the gear set comprises a first control gear (24) connected with a heat preservation control power source (23), the first control gear (24) is matched with a second control gear (25), the second control gear (25) is arranged on the rack (1), the second control gear (25) is connected with a first control bevel gear (26), the first control bevel gear (26) is matched with a second control bevel gear (27), and the second control bevel gear (27) is arranged at one end of a control screw rod (28).

3. The heating apparatus of a vacuum melting furnace for producing a high electric resistance electrothermal alloy wire according to claim 1, characterized in that: the heat-preservation control assembly is uniformly provided with at least four groups along the circumference of the rack (1), and the connection relations among the same parts are the same.

4. The heating apparatus of a vacuum melting furnace for producing high-resistance electrothermal alloy wires according to claim 3, characterized in that: every group the heat preservation cloth in the heat preservation control assembly tightens up box (47) changes roller one (43) and the equal fixedly connected with synchronizing gear (45) of heat preservation cloth commentaries on classics roller two (44) upside, and two synchronizing gear (45) meshing, two synchronizing gear (45) downside all is provided with torsional spring (46).

5. The heating apparatus of a vacuum melting furnace for producing high-resistance electrothermal alloy wires according to claim 4, wherein: one heat preservation cloth roller (43) of one group of heat preservation control assemblies is connected with one end of heat preservation cloth (42), the other end of the heat preservation cloth (42) is arranged on a heat preservation cloth roller II (44) of the other group of heat preservation control assemblies adjacent to the one group of heat preservation control assemblies, and the middle parts of the heat preservation cloth (42) are fixed on fixing strips (40) of the one group of heat preservation control assemblies.

6. The heating apparatus of a vacuum melting furnace for producing a high electric resistance electrothermal alloy wire according to claim 1, characterized in that: fixing device (2) is including setting up lift cylinder (5) in frame (1), lift cylinder (5) with place set (6) and be connected, place and be provided with a plurality of balls (7) on set (6), evenly be provided with at least three splint (8) along placing set (6) circumference.

7. The heating apparatus of a vacuum melting furnace for producing high-resistance electrothermal alloy wires according to claim 6, wherein: the heating device (3) comprises a heating fixing plate (17) arranged on the rack (1), a top platform (16) is arranged at the central position of the heating fixing plate (17), a square hole is formed in the top platform (16), a heating resistance wire (18) is arranged on the heating fixing plate (17), a cooling fan (19) is arranged on the outer side of the heating fixing plate (17), a cooling inner toothed ring (22) is arranged on the cooling fan (19), the cooling inner toothed ring (22) is matched with a cooling gear (21), the cooling gear (21) is connected with a cooling power source (20), and the cooling power source (20) is arranged on the heating fixing plate (17).

8. The heating apparatus of a vacuum melting furnace for producing high-resistance electrothermal alloy wires according to claim 7, wherein: all splint (8) are equallyd divide and are do not connected with a splint connecting plate (9), be provided with splint rack (11), all on splint connecting plate (9) splint rack (11) all cooperate with splint gear (12), splint gear (12) set up in the splint change (13) outside, splint change (13) set up and are placing set (6) downside central point and put, splint change (13) inboard is provided with the screw thread, the inboard screw thread of splint change (13) and screw thread section of thick bamboo (14) outside screw-thread fit, screw thread section of thick bamboo (14) and location square column (15) sliding fit, location square column (15) set up and are placing set (6) downside central point.