Carrying and stacking robot for food industrial processing

Abstract

The invention relates to the field of food stacking devices, in particular to a carrying and stacking robot for food industrial processing. The device comprises a mechanical arm, a bearing frame, a guide ring, a limiting plate, a conveying roller mechanism and a switching mechanism. The mechanical arm is provided with a control end; the bearing frame is connected to the control end; the two guide rings are horizontally and symmetrically arranged on the bearing frame; the conveying roller mechanism comprises a plurality of groups of conveying roller assemblies which are distributed side by side along the trend of the outer contour of the guide ring, each conveying roller assembly comprises a roller group and two groups of moving assemblies which are symmetrically distributed relative to the roller group, each moving assembly comprises a moving frame for rotationally mounting the roller group and a roller assembly rolling on the guide ring, and the roller assemblies are rotationally arranged on the moving frames; the switching mechanisms are arranged on the two guide rings respectively, drive the movable frame to move and comprise three chain wheels which are rotationally arranged on the guide rings and distributed at the positions of the triangles respectively. A whole layer of goods can be carried and stacked at a time, and the stacking efficiency is high.

Description

Technical Field

[0001] The invention relates to the field of food palletizing devices, and in particular to a handling and palletizing robot for industrialized food processing. Background Art

[0002] In the food industrial processing and production industry, handling and palletizing robots can be used for palletizing food after packaging. The packaged food can be stacked according to a certain pattern, saving labor and improving handling and palletizing efficiency. For example, in the production of drinking water, after the drinking water is processed, multiple bottles of drinking water need to be packaged in cartons or plastic films, and then the boxes or bags of drinking water are palletized for subsequent transportation. In addition, other types of bottled beverages can also be palletized by handling and palletizing robots after being packaged into boxes or bags.

[0003] Chinese patent announcement number CN213801963U announces a four-axis handling and palletizing robot, including a four-axis palletizing robot body, a rectangular frame is rotatably installed on the four-axis palletizing robot body, a clamping mechanism is fixedly installed on the rectangular frame, the clamping mechanism includes a box body, the box body passes through the rectangular frame and is fixedly connected to the inner wall of the rectangular frame, two sliding holes are opened on the inner wall of the box body away from the four-axis palletizing robot body, and cross bars are slidably installed in the two sliding holes. The two cross bars pass through the corresponding sliding holes respectively, and two connecting rods are hinged on the cross bar. The ends of the two connecting rods away from the cross bar are hinged with the same clamping plate, and the sides of the two cross bars away from each other are fixedly installed with mounting plates, and cylinders are hinged on the two mounting plates. The handling and palletizing robot is simple to operate and easy to use, can adapt to boxes of different sizes, has high stability, good clamping effect, and wide applicability.

[0004] However, the above technical solution has the following shortcomings: only one cargo can be transported at a time, and then the cargo can be placed on the same layer. After stacking one layer of cargo, the cargo needs to be transported back and forth several times and placed on the upper layer, resulting in low stacking efficiency. Summary of the invention

[0005] The purpose of the present invention is to solve the problems existing in the background technology and to provide a handling and palletizing robot for industrialized food processing, which can handle and palletize a whole layer of goods at one time and has high palletizing efficiency.

[0006] The technical solution of the present invention is a handling and stacking robot for industrialized food processing, comprising a mechanical arm, a carrier, a guide ring, a limit plate, a conveying roller mechanism and a switching mechanism; the mechanical arm has a manipulation end; the carrier is connected to the manipulation end of the mechanical arm; two guide rings are horizontally symmetrically arranged on the carrier; the conveying roller mechanism comprises a plurality of conveying roller assemblies arranged side by side along the outer contour of the guide ring, the conveying roller assembly comprises a roller group and two groups of moving assemblies symmetrically arranged about the roller group, the moving assembly comprises a moving frame for rotatably mounting the roller group and a roller assembly rolling on the guide ring, the roller assembly being rotatably arranged on the moving frame; the switching mechanism One group is arranged on each of the two guide rings to drive the mobile frame to move, including rotating three sprockets arranged on the guide rings and respectively distributed at the triangles of the triangle, two of the three sprockets are at the same height, and the remaining sprocket is higher than the two sprockets, and when the switching mechanism adjusts the conveying roller mechanism to be horizontally distributed between the two sprockets, the conveying roller mechanism is in a supporting state, and when the switching mechanism moves the conveying roller mechanism away from between the two sprockets, the conveying roller mechanism is in a discharging state; a limit plate is arranged on the carrier frame, which limits the cargo collection range when the conveying roller mechanism is in the supporting state, and blocks the cargo when the conveying roller mechanism is in the discharging state.

[0007] Preferably, the guide ring is a triangular ring structure with a rounded transition at the turning point of the triangular ring structure, and guide bosses are arranged on the inner and outer sides along the contour. The roller assembly includes roller one and roller two which roll on the guide bosses on both sides respectively, and roller one and roller two have an annular rolling groove for the guide boss to extend into.

[0008] Preferably, the switching mechanism also includes a chain meshingly connected to the three sprockets and a reduction motor 1 arranged on the guide ring, the reduction motor 1 is drivingly connected to a sprocket, the chain includes a plurality of chain links hinged in sequence in a ring shape, and the moving assembly also includes a connecting frame connected to the chain links, a rod connected to the outer end of the connecting frame, and a cylinder arranged on the moving frame and for the rod to slide.

[0009] Preferably, the roller group includes a rotating shaft rotatably arranged on the moving frame and a roller coaxially arranged on the rotating shaft.

[0010] Preferably, it also includes a driving mechanism, which includes a power component arranged on a mobile frame and driving a rotating shaft to rotate, and a linkage component that connects multiple rotating shafts, the linkage component includes a gear 1 arranged on each of the multiple rotating shafts and a connecting component that connects two adjacent gears, the connecting component includes a plate 1 and a plate 2 arranged on two adjacent rotating shafts, an intermediate shaft that is connected to the plate 1 and the plate 2 for simultaneous rotation, and a gear 2 arranged on the intermediate shaft, and the gear 2 is meshed and connected with two adjacent gear 1s.

[0011] Preferably, the roller is rotatably arranged on a rotating shaft, a stop platform is arranged at the axial end face of the roller, a mounting sleeve is arranged on the rotating shaft, a sliding rod is slidably arranged on the mounting sleeve, a pushing platform is connected to the outer end of the sliding rod, a spring arranged on the outer periphery of the sliding rod is connected between the mounting sleeve and the pushing platform, the pushing platform has a first inclined surface, and the stop platform has a second inclined surface for the first inclined surface of the pushing platform to push.

[0012] Preferably, the limit plate is a horizontally distributed U-shaped plate with a flared opening, an electric push rod is vertically arranged on the support frame, and a baffle is arranged at the bottom movable end of the electric push rod that can move down to the opening of the limit plate or move upward from the opening.

[0013] Preferably, the three sprockets are respectively distributed at three corners of an equilateral triangle.

[0014] Compared with the prior art, the present invention has the following beneficial technical effects:

[0015] The present invention can transport and palletize a whole layer of goods at one time, and the palletizing efficiency is high. The transport and palletizing robot for industrialized food processing adjusts the conveying roller mechanism to a supporting state, and aligns and connects with the terminal end of the conveyor, and the conveyor transports multiple goods to the conveying roller mechanism in sequence. Then, the transport and palletizing robot transfers the conveying roller mechanism to the top of the position to be palletized, switches the conveying roller mechanism to a discharging state, gradually releases the support for multiple goods, and the multiple goods automatically fall down, realizing full-layer palletizing. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a structural schematic diagram of an embodiment of the present invention;

[0017] Figure 2 A schematic diagram of the structure when multiple rollers are removed to allow the cargo to fall;

[0018] Figure 3 Schematic diagram of the distribution of the connecting frame and the roller one;

[0019] Figure 4 A partial structural cross-sectional view of an embodiment of the present invention;

[0020] Figure 5 for Figure 4 A magnified view of the structure at center.

[0021] Figure numerals: 1, mechanical arm; 2, counterweight; 3, carrier frame; 4, guide ring; 5, reduction motor 1; 6, sprocket; 7, chain; 71, chain link; 8, moving frame; 9, cylinder; 10, rod; 11, connecting frame; 12, roller 1; 13, roller 2; 14, rotating shaft; 15, roller; 16, mounting sleeve; 17, sliding rod; 18, push table; 19, spring; 20, baffle; 21, mounting seat; 22, reduction motor 2; 23, driving gear; 24, driven gear; 25, gear 1; 26, gear 2; 27, plate 1; 28, plate 2; 29, limit plate; 30, baffle; 31, electric push rod; 32, shielding cover. DETAILED DESCRIPTION

[0022] Embodiment 1, as Figure 1-Figure 5 As shown, the present embodiment provides a handling and palletizing robot for industrialized food processing, comprising a robot arm 1, a carrier frame 3, a guide ring 4, a limit plate 29, a conveying roller mechanism and a switching mechanism.

[0023] like Figure 1 As shown, the robot arm 1 has a manipulation end, which can move the carrier 3 to a desired position. The carrier 3 is connected to the manipulation end of the robot arm 1. A counterweight 2 is provided at the rear side of the robot arm 1. The counterweight 2 and the carrier 3 are respectively located on both sides of the robot arm 1. The counterweight 2 plays a counterweight role to prevent the entire robot from tipping over due to the heavy cargo on one side of the carrier 3.

[0024] Two guide rings 4 are horizontally symmetrically arranged on the carrier 3. The guide rings 4 are triangular ring structures, and the corners of the triangular ring structures are rounded. The inner and outer sides are provided with guide bosses along the contour, and the guide bosses also have rounded corners at the structural turning points. The outer guide bosses and the inner guide bosses are equidistantly offset.

[0025] The conveying roller mechanism includes a plurality of conveying roller assemblies arranged side by side along the outer contour of the guide ring 4. The conveying roller assembly includes a roller group and two groups of moving assemblies symmetrically distributed about the roller group. The roller group includes a rotating shaft 14 rotatably arranged on the moving frame 8 and a roller 15 coaxially arranged on the rotating shaft 14, and the roller 15 is used to support the goods. The moving assembly includes a connecting frame 11, a moving frame 8 for rotating the roller group, a roller assembly rolling on the guide ring 4, a rod 10 connected to the outer end of the connecting frame 11, and a cylinder 9 arranged on the moving frame 8 and for the rod 10 to slide. The roller assembly is rotatably arranged on the moving frame 8, specifically, the roller assembly includes a roller 12 and a roller 2 13 rolling at the guide bosses on both sides, respectively, and the roller 12 and the roller 2 13 both have an annular rolling groove for the guide bosses to extend into. The roller 12 and the roller 2 13 can accurately roll along the guide bosses on the guide ring 4 without falling off.

[0026] like Figure 2-Figure 4As shown, a switching mechanism is provided on each of the two guide rings 4, and the switching mechanism can drive the mobile frame 8 to move. The switching mechanism includes three sprocket wheels 6 rotatably provided on the guide ring 4 and respectively distributed at the triangles of the triangle, a chain 7 meshingly connected to the three sprocket wheels 6, and a reduction motor 5 provided on the guide ring 4. Specifically, the three sprocket wheels 6 are distributed at the triangles of the equilateral triangle. Two of the three sprocket wheels 6 are of equal height, and the remaining sprocket wheel 6 is higher than the two sprocket wheels 6, and the reduction motor 5 is drivingly connected to the higher sprocket wheel 6. The position where the sprocket wheel 6 is rotatably provided on the guide ring 4 is located between the inner guide boss and the outer guide boss. The chain 7 includes a plurality of chain links 71 hinged in sequence in a ring shape, and a single chain link 71 is connected to a single connecting frame 11. When the chain link 71 drives the connecting frame 11 to move to the vicinity of the sprocket 6, the distance from the chain link 71 to the outer guide boss becomes shorter, and the rod 10 will extend into the inner side of the tube 9 to adapt to the change in distance, but it can ensure that the moving component is still driven by the chain link 71 and no structural interference will occur.

[0027] A shielding cover 32 may be additionally provided on the outer side of the carrier frame 3 , and a passage for the cylinder 9 and the rod 10 to pass through is reserved between the shielding cover 32 and the guide ring 4 . The shielding cover 32 can protect the sprocket 6 and the chain 7 to a certain extent.

[0028] When the switching mechanism adjusts the conveyor roller mechanism to be horizontally distributed between the two sprockets 6, the conveyor roller mechanism is in a supporting state, and multiple groups of conveyor roller assemblies are horizontally distributed side by side, and multiple goods can be conveyed to the multiple groups of conveyor roller assemblies. The conveyor roller mechanism can carry a maximum load of 1000kg of goods. When the switching mechanism moves the conveyor roller mechanism away from between the two sprockets 6, the conveyor roller mechanism is in a discharging state, and multiple groups of conveyor roller assemblies bypass the rear side of the limit plate 29 in turn, and release the support for multiple goods (boxes or bottles of beverages) in turn. Multiple goods will fall down in turn due to their own gravity, realizing the stacking of the entire layer.

[0029] The limit plate 29 is arranged on the carrier 3, and limits the cargo collection range when the conveying roller mechanism is in the supporting state, so as to prevent the cargo from falling from the conveying roller mechanism. When the conveying roller mechanism is in the discharging state, the cargo is blocked. Specifically, for a plurality of cargoes that have been neatly collected on the conveying roller mechanism, after the conveying roller mechanism is removed, the plurality of cargoes will not be carried but will automatically fall down. The limit plate 29 is used to prevent the cargoes from moving with the conveying roller mechanism, and limit the cargoes to a fixed area for falling.

[0030] This embodiment can transport and palletize a whole layer of goods at a time, and the palletizing efficiency is high. The transport and palletizing robot for industrialized food processing is arranged on one side of the terminal end of an existing conveyor for conveying goods. When transporting goods, the conveying roller mechanism is adjusted to a supporting state and aligned and connected with the terminal end of the conveyor, and the conveyor transports multiple goods to the conveying roller mechanism in sequence. Then, the transport and palletizing robot transfers the conveying roller mechanism to the top of the position to be palletized, switches the conveying roller mechanism to the discharge state, gradually releases the support for multiple goods, and multiple goods automatically fall down to achieve full-layer palletizing.

[0031] When using this food industrial processing handling and palletizing robot to receive multiple goods delivered by the conveyor, there are two receiving methods:

[0032] Receiving method 1: Multiple goods have been regularly distributed on the conveyor according to the required stacking rules. The conveyor roller mechanism is aligned with the end of the conveyor and keeps the position unchanged. The conveyor directly transports multiple goods in an orderly manner to the conveyor roller mechanism.

[0033] Receiving method 2: Multiple goods are distributed side by side on the conveyor, and the conveyor transports them in sequence in one direction. After the conveyor roller mechanism receives a good, the food industrial processing handling and stacking robot adjusts the lateral position of the conveyor roller mechanism (adjusted in the lateral direction perpendicular to the conveying direction of the conveyor) and receives the multiple goods in order in rows and columns.

[0034] Embodiment 2, as Figure 1-Figure 5 As shown, the present embodiment proposes a handling and palletizing robot for industrialized food processing. Compared with the first embodiment, the handling and palletizing robot in the present embodiment further includes a driving mechanism, and the driving mechanism includes a power assembly disposed on a mobile frame 8 and driving a rotating shaft 14 to rotate, and a linkage assembly that transmission-connects multiple rotating shafts 14. The power assembly includes a mounting seat 21 disposed on a mobile frame 8, a reduction motor 22 disposed on the mounting seat 21, a driving gear 23 connected to the output end of the reduction motor 22, and a driven gear 24 meshingly connected to the driving gear 23, and the driven gear 24 is coaxially disposed on the rotating shaft 14 in the conveying roller assembly to which the mobile frame 8 belongs.

[0035] The reduction motor 22 can drive the driving gear 23 to rotate, and the driving gear 23 drives the driven gear 24 to rotate, thereby driving the rotating shaft 14 to rotate. The linkage assembly includes a gear 1 25 arranged on each of the multiple rotating shafts 14 and a connecting assembly connecting two adjacent gears 1 25. The connecting assembly includes a plate 1 27 and a plate 2 28 arranged on two adjacent rotating shafts 14, an intermediate shaft connected to the plate 1 27 and the plate 2 28 for simultaneous rotation, and a gear 2 26 arranged on the intermediate shaft, and the gear 2 26 is meshed and connected with two adjacent gears 1 25. When multiple conveying roller assemblies are distributed side by side, the multiple rotating shafts 14 are linked through the gear 1 25 and the connecting assembly, and can rotate in the same direction. Specifically, when a rotating shaft 14 rotates, it drives the gear 1 25 on the rotating shaft 14, and the gear 1 25 drives the gear 2 26, and the gear 2 26 drives another adjacent gear 1 25, thereby driving another adjacent rotating shaft 14 to rotate. When multiple rotating shafts 14 rotate synchronously, multiple rollers 15 can be driven to rotate synchronously. Multiple rollers 15 can continue to transport the goods transported by the conveyor inward until multiple goods are neatly collected on the conveying roller mechanism. At this time, the limiting plate 29 on the rear side can prevent multiple goods from falling.

[0036] In the process of switching the conveying roller mechanism to the unloading state, when the conveying roller assembly passes through the sprocket 6, because the chain 7 is not equidistantly offset from the guide bosses on the inner and outer sides of the guide ring 4, the distance between two adjacent gears 1 25 will become smaller, and the gear 2 26 will be driven to move through the plate 1 27 and the plate 2 28. The plate 1 27 and the plate 2 28 are designed to be connected by an intermediate shaft to avoid jamming between the structures during the movement of the conveying roller assembly.

[0037] This embodiment can drive multiple rollers 15 to rotate through a driving mechanism, and can transport multiple goods to the transport roller mechanism in a supporting state.

[0038] Embodiment three, as Figure 1-Figure 5 As shown, the present embodiment proposes a handling and stacking robot for industrialized processing of food. Compared with the second embodiment, in the present embodiment, the roller 15 is rotatably arranged on the rotating shaft 14, a stopper 20 is arranged at the axial end face of the roller 15, a mounting sleeve 16 is arranged on the rotating shaft 14, a slide rod 17 is slidably arranged on the mounting sleeve 16, a push platform 18 is connected to the outer end of the slide rod 17, a spring 19 is connected between the mounting sleeve 16 and the push platform 18 and is sleeved on the outer periphery of the slide rod 17, the push platform 18 has an inclined surface 1, and the stopper 20 has an inclined surface 2 for the inclined surface 1 of the push platform 18 to push.

[0039] In this embodiment, when the rotating shaft 14 rotates clockwise, the stopper 20 can be pushed through the mounting sleeve 16, the slide bar 17 and the pusher 18, thereby driving the roller 15 to rotate and transport the goods. When the goods need to be unloaded for palletizing, the conveying roller mechanism is moved away from under the goods. Due to the friction between the roller 15 and the goods, the roller 15 rolls at the bottom of the goods. The roller 15 pushes the pusher 18 inward through the inclined plane 2 and the inclined plane 1, and the pusher 18 compresses the spring 19. That is to say, when the goods are unloaded, the roller 15 and the goods are in rolling contact, which reduces the wear of the roller 15 and the goods.

[0040] Embodiment 4, as Figure 1-Figure 5 As shown, the present embodiment proposes a handling and stacking robot for industrialized food processing. Compared with the first embodiment, in the present embodiment, the limit plate 29 is a horizontally distributed U-shaped plate, and the opening is flared. An electric push rod 31 is vertically arranged on the carrier frame 3, and a baffle 30 is arranged at the bottom movable end of the electric push rod 31, which can move down to the opening of the limit plate 29 or move upward from the opening.

[0041] In this embodiment, when the food industrial processing handling and palletizing robot is used to collect goods transported from the conveyor, the baffle 30 moves upward from the opening of the limit plate 29. After the goods are collected, the electric push rod 31 pushes the baffle 30 downward, and the baffle 30 is blocked at the opening of the limit plate 29. The handling and palletizing robot transfers the goods to the palletizing position. During this process, the limit plate 29 and the baffle 30 effectively limit the range of the goods, and the goods will not be thrown off.

[0042] The embodiments of the present invention are described in detail above with reference to the accompanying drawings, but the present invention is not limited thereto, and various changes can be made within the knowledge scope of technicians in the relevant technical field without departing from the purpose of the present invention.

Claims

1. A handling and palletizing robot for industrialized food processing, comprising a mechanical arm (1) having a manipulator end, characterized in that: Also includes: A carrier frame (3) connected to the manipulating end of the mechanical arm (1); Two guide rings (4) are horizontally and symmetrically arranged on the carrier frame (3); The conveying roller mechanism comprises a plurality of conveying roller assemblies arranged side by side along the outer contour of a guide ring (4), the conveying roller assemblies comprising a roller group and two groups of moving assemblies symmetrically arranged about the roller group, the moving assemblies comprising a moving frame (8) for rotatably mounting the roller group and a roller assembly rolling on the guide ring (4), the roller assembly being rotatably mounted on the moving frame (8); A switching mechanism is provided on each of the two guide rings (4) to drive the moving frame (8) to move, including rotating three sprockets (6) provided on the guide ring (4) and respectively distributed at the three corners of the triangle, two of the three sprockets (6) being of equal height, and the remaining sprocket (6) being higher than the two sprockets (6), and when the switching mechanism adjusts the conveying roller mechanism to be horizontally distributed between the two sprockets (6), the conveying roller mechanism is in a supporting state, and when the switching mechanism moves the conveying roller mechanism away from between the two sprockets (6), the conveying roller mechanism is in a discharging state; The limiting plate (29) is arranged on the bearing frame (3) to limit the cargo collection range when the conveying roller mechanism is in a supporting state and to block the cargo when the conveying roller mechanism is in a discharging state.

2. A handling and stacking robot for industrialized food processing according to claim 1, characterized in that: The guide ring (4) is a triangular ring structure with a rounded transition at the turning point of the triangular ring structure. Guide bosses are arranged on the inner and outer sides along the contour. The roller assembly comprises a roller 1 (12) and a roller 2 (13) which roll on the guide bosses on both sides respectively. The roller 1 (12) and the roller 2 (13) both have an annular rolling groove for the guide bosses to extend into.

3. A handling and palletizing robot for industrialized food processing according to claim 1, characterized in that: The switching mechanism also includes a chain (7) meshingly connected to the three sprockets (6) and a reduction motor (5) arranged on the guide ring (4), the reduction motor (5) being drivingly connected to one sprocket (6), the chain (7) including a plurality of chain links (71) hinged in sequence in a ring shape, and the moving assembly also including a connecting frame (11) connected to the chain links (71), a rod (10) connected to the outer end of the connecting frame (11), and a cylinder (9) arranged on the moving frame (8) and for the rod (10) to slide.

4. The food industrial processing handling and palletizing robot according to claim 1, characterized in that: The roller group comprises a rotating shaft (14) rotatably arranged on a moving frame (8) and a roller (15) coaxially arranged on the rotating shaft (14).

5. A handling and palletizing robot for industrialized food processing according to claim 4, characterized in that: The invention also comprises a driving mechanism, the driving mechanism comprising a power assembly arranged on a moving frame (8) and driving a rotating shaft (14) to rotate, and a linkage assembly for connecting a plurality of rotating shafts (14) in a transmission manner, the linkage assembly comprising a gear 1 (25) arranged on each of the plurality of rotating shafts (14) and a connection assembly for connecting two adjacent gear 1s (25), the connection assembly comprising a plate 1 (27) and a plate 2 (28) arranged on two adjacent rotating shafts (14), an intermediate shaft connected to the plate 1 (27) and the plate 2 (28) for simultaneous rotation, and a gear 2 (26) arranged on the intermediate shaft, the gear 2 (26) being meshedly connected with two adjacent gear 1s (25).

6. A handling and palletizing robot for industrialized food processing according to claim 5, characterized in that: The roller (15) is rotatably arranged on the rotating shaft (14), a stopper (20) is arranged at the axial end surface of the roller (15), a mounting sleeve (16) is arranged on the rotating shaft (14), a slide bar (17) is slidably arranged on the mounting sleeve (16), a push platform (18) is connected to the outer end of the slide bar (17), a spring (19) sleeved on the outer periphery of the slide bar (17) is connected between the mounting sleeve (16) and the push platform (18), the push platform (18) has a first inclined surface, and the stopper (20) has a second inclined surface for the first inclined surface of the push platform (18) to push.

7. The food industrial processing handling and palletizing robot according to claim 1, characterized in that: The limiting plate (29) is a horizontally distributed U-shaped plate, and the opening is expanded. An electric push rod (31) is vertically arranged on the support frame (3), and a baffle (30) is arranged at the bottom movable end of the electric push rod (31) and can move downward to the opening of the limiting plate (29) or move upward from the opening.

8. The food industrial processing handling and palletizing robot according to claim 1, characterized in that: The three sprocket wheels (6) are respectively distributed at the three corners of the equilateral triangle.

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