Welding equipment for hydraulic engineering pipeline support
Technical Field
The invention relates to the technical field of welding equipment, in particular to welding equipment for a hydraulic engineering pipeline bracket.
Background
There is a need for a large number of pipes in hydraulic engineering for the collection, transportation, distribution and regulation of water resources. Common piping materials used in hydraulic engineering include various steels (e.g., carbon steel, stainless steel), cast iron, plastics (e.g., polyethylene, polyvinyl chloride), concrete pipes, and the like. The pipeline has various application scenes in hydraulic engineering, including reservoir water supply, river rehabilitation, hydrologic monitoring, farmland irrigation, urban water supply and drainage, sea water desalination and the like. The dimensions (diameter and wall thickness) of the pipe are dependent on engineering requirements, and it is possible to use small pipes to large diameter water pipes. The connection mode of the pipelines comprises welding, flange connection, threaded connection, socket connection and the like, wherein welding is a common connection mode and can provide firm connection effect.
When welding the pipes, it is necessary to ensure that the two pipes are in a coaxial position, and it is necessary to perform centering treatment on the two pipes, in order to ensure that the welded pipes are structurally stable, and that the pipes are not dislocated or unnecessarily stressed due to improper welding. The two pipelines can be centered by using the clamp, but after the clamp is used, the clamp can fix the two pipelines, and at the moment, the distance between the two pipelines cannot be adjusted. When welding, the pipe material expands due to heat, and if the distance is too small, the pipe may be deformed or the stress at the weld may be too large. Proper spacing may reduce these risks. Therefore, the distance between the two pipelines needs to be properly adjusted, and the existing welding equipment cannot accurately adjust the distance between the pipelines with different sizes and lengths.
Disclosure of Invention
The invention aims to provide welding equipment for a hydraulic engineering pipeline bracket, which can position the center of a pipeline and is convenient for adjusting the distance between two pipelines, aiming at the problem that the prior welding equipment in the background art can not accurately adjust the distance between pipelines with different sizes and lengths.
The technical scheme of the invention is that the welding equipment for the hydraulic engineering pipeline bracket comprises a base, a controller fixedly arranged on the base, and further comprises:
The two support cylinders are fixedly arranged on the base and used for placing the pipelines, three centering mechanisms are arranged on the support cylinders, and the centering mechanisms center the pipelines in the two support cylinders;
Two centering mechanisms positioned on two sides of the same supporting cylinder are provided with interval adjusting mechanisms, and the interval adjusting mechanisms drive the pipeline to move in the supporting cylinder;
A fixing mechanism is arranged on one centering mechanism positioned in the middle of the same supporting cylinder, and the fixing mechanism is used for fixing a pipeline in the supporting cylinder;
The first centering driving mechanism drives a plurality of centering mechanisms connected with the interval adjusting mechanisms on the two supporting cylinders to move at the same time;
The second centering driving mechanism drives the centering mechanisms connected with the fixing mechanisms on the two supporting cylinders to move at the same time;
and the welding gun is rotatably arranged between the two supporting cylinders.
Optionally, the centering mechanism includes a plurality of supporting seats of fixed mounting on the supporting cylinder, slidable mounting on the driving ring on the supporting seat, be equipped with the spout on the driving ring, supporting seat and spout sliding connection, slidable mounting has a plurality of centering bars on the supporting cylinder, slidable mounting has the connecting seat on the centering bar, fixed mounting has the spring on the connecting seat, the other end and the centering bar fixed connection of spring, rotate on the driving ring and install the driving rod, the other end and the connecting seat of driving rod rotate to be connected.
Optionally, the interval adjustment mechanism includes the gyro wheel seat of fixed mounting on the centering rod that is located the centering mechanism on support section of thick bamboo both sides, rotates the gyro wheel of installing on the gyro wheel seat, the first band pulley of fixed mounting on the gyro wheel, rotate the second band pulley of installing on the centering rod, locate the drive belt on first band pulley and the second band pulley, the gear of fixed mounting on the second band pulley, the bracing piece of fixed mounting on the centering rod, slidable mounting on the bracing piece, rack and gear intermeshing, one of them fixed mounting has the motor cabinet on the centering rod, fixed mounting has first motor on the motor cabinet, fixed mounting has the internal thread pole on the output shaft of first motor, threaded rod internal thread is connected with the lead screw, install the linkage subassembly between a plurality of racks on the same interval adjustment mechanism, the linkage subassembly drives a plurality of racks and carries out synchronous motion.
Optionally, the linkage assembly includes the installation piece of fixed mounting on the rack, rotates two first connecting rods of installing on the installation piece, rotates the second connecting rod of installing on first connecting rod, adjacent two the second connecting rod is rotated mutually and is connected.
Optionally, the fixing mechanism includes a fastening pad fixedly mounted on a centering rod on a centering mechanism in the middle of the supporting cylinder, the fastening pad is made of deformable rubber materials, and the fastening pad coats the pipeline and applies friction force to the pipeline.
Optionally, the first centering driving mechanism includes a first sector rack fixedly installed on driving rings at two sides of the supporting cylinder, a first centering driving motor fixedly installed on the base, a first transmission shaft fixedly installed on the first centering driving motor, four first centering driving gears fixedly installed on the first transmission shaft, and the four first centering driving gears are in one-to-one correspondence with the four first sector racks and meshed with each other.
Optionally, the second centering driving mechanism comprises a second centering driving motor fixedly installed on the base, a second transmission shaft fixedly installed on the second centering driving motor, a second centering driving gear fixedly installed on the second transmission shaft, and a second sector rack fixedly installed on a driving ring positioned in the middle on the supporting cylinder, wherein the two second sector racks are in one-to-one correspondence with the two second centering driving gears and meshed with each other.
Optionally, the end rotation of support section of thick bamboo is installed the gag lever post, gag lever post threaded connection has the nut, be equipped with the spacing hole that corresponds with the nut on the support section of thick bamboo.
Optionally, fixed mounting has the welder seat on the support section of thick bamboo, be equipped with the slide on the welder seat, slidable mounting has the commentaries on classics piece in the slide, welding gun slidable mounting is on changeing the piece, one of them slidable mounting has the second motor on the welder seat, another slidable mounting has welding drive gear and fixed mounting to have the ring gear on the welder seat, the coaxial fixed connection of output shaft and welding drive gear of second motor, welding drive gear and ring gear intermeshing.
Optionally, two slide bars are fixedly installed on the rotating block, a supporting plate is slidably installed on the slide bars, two lifting screw rods are rotatably installed on the rotating block, the supporting plate is in threaded connection with the lifting screw rods, and a linkage belt is installed on the two lifting screw rods.
Compared with the prior art, the invention has the following beneficial technical effects:
The first positioning driving motor drives the driving ring to rotate, so that the driving rods on the driving ring are driven to synchronously swing, and the synchronous swing of the driving rods pushes the centering rod to move towards the direction close to the pipeline. The roller seat is driven to move towards the direction close to the pipeline, so that the roller is contacted with the pipeline, the pipelines in the two connecting cylinders can be moved to the coaxial position, the welded pipeline can be ensured to be structurally stable, and the pipeline dislocation or unnecessary stress can not be caused by improper welding.
Further, the pipeline is pressurized through the roller, a certain friction force is generated between the roller and the pipeline, the first motor is started to drive the racks to synchronously move, the second belt wheel is driven to rotate, the first belt wheel can be driven to rotate through the transmission of the transmission belt, the roller is driven to rotate, and the pipeline can be driven to move through the friction force between the roller and the pipeline. And then carry out position adjustment to the pipeline, and then be convenient for adjust the interval between two pipelines. The pipeline deformation or the overlarge stress at the welding seam caused by the overlarge spacing is prevented, and the quality of the welding seam can be ensured.
Still further, through the frictional force between gyro wheel and the pipeline to the pipeline is driven, can carry out the interval to the pipeline of different diameters and different length and adjust, strong adaptability can adapt to the variety of the pipeline that need use different sizes different length when hydraulic engineering construction.
Drawings
FIG. 1 is a schematic diagram of an embodiment of the present invention;
FIG. 2 is a schematic diagram of a side structure of the present invention;
FIG. 3 is a schematic view of the position of the support cylinder and drive ring of the present invention;
FIG. 4 is a schematic view of the structure of the first and second links of the present invention;
FIG. 5 is a schematic view of the centering mechanism and the roller of the present invention;
FIG. 6 is a schematic view of the centering mechanism and the fastening pad of the present invention;
FIG. 7 is a schematic diagram of a spacing adjustment mechanism according to the present invention;
FIG. 8 is a schematic view of a welding gun according to the present invention;
FIG. 9 is an enlarged view of a portion of the invention at A in FIG. 3;
fig. 10 is a partial enlarged view of the present invention at B in fig. 4.
Reference numerals 1, base, 101, controller, 2, support cylinder, 3, drive ring, 301, support seat, 302, chute, 303, centering rod, 304, connection seat, 305, spring, 306, drive rod, 307, first sector rack, 308, first centering drive gear, 309, first centering drive motor, 310, first transmission shaft, 4, second centering drive motor, 401, second centering drive gear, 402, second sector rack, 403, second transmission shaft, 5, fastening pad, 6, roller seat, 601, roller, 602, first pulley, 603, transmission belt, 604, gear, 605, motor seat, 606, first motor, 607, internal threaded rod, 608, screw, 609, support rod, 610, rack, 611, second pulley, 7, mounting block, 701, first connecting rod, 702, second connecting rod, 8, limit rod, 801, 9, welding gun seat, 901, slideway, rotating block, 903, 904, lifting screw, 905, support plate, linkage belt, 908, gear, drive ring 910, welding rod, welding wire, and 909.
Detailed Description
The following description of the embodiments of the present invention will be made apparent and fully in view of the accompanying drawings, in which some, but not all embodiments of the invention are shown.
The components of the embodiments of the present invention generally described and illustrated in the figures herein may be arranged and designed in a wide variety of different configurations. Thus, the following detailed description of the embodiments of the invention, as presented in the figures, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention.
All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
In the description of the present invention, it should be noted that the directions or positional relationships indicated by the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc. are based on the directions or positional relationships shown in the drawings, are merely for convenience of describing the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.
In the description of the present invention, unless explicitly stated or limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be, for example, fixedly connected, detachably connected, or integrally connected, mechanically connected, electrically connected, directly connected, indirectly connected via an intervening medium, or in communication between two elements. The specific meaning of the above terms in the present invention will be understood in specific cases by those of ordinary skill in the art.
Example 1
As shown in fig. 1, the welding device for hydraulic engineering pipeline support provided by the invention comprises a base 1 and a controller 101 fixedly arranged on the base 1. The device can be controlled by the controller 101.
As shown in fig. 1-6, two support barrels 2 fixedly installed on a base 1 and used for placing pipelines are provided, a limit rod 8 is rotatably installed at the end of the support barrel 2, a nut 801 is connected with the limit rod 8 in a threaded manner, and limit holes corresponding to the nut 801 are formed in the support barrel 2. After the nut 801 is moved to a position coaxial with the limiting hole by rotating the limiting rod 8, the nut 801 is inserted into the limiting hole, and at the moment, the supporting cylinder 2 is blocked by the limiting rod 8. And then the end of the pipeline to be welded is polished and leveled and then inserted into the support cylinder 2, and the end of the pipeline to be welded is abutted against the limit rod 8. The stop bar 8 locates the initial spacing between the two pipes. Three centering mechanisms are arranged on the supporting cylinders 2, and the centering mechanisms center the pipelines in the two supporting cylinders 2. The pipes are then centered by a centering mechanism, moving the two pipes to a coaxial position. The centering mechanism comprises a plurality of supporting seats 301 fixedly mounted on the supporting cylinder 2, a driving ring 3 slidably mounted on the supporting seats 301, a sliding groove 302 is formed in the driving ring 3, the supporting seats 301 are slidably connected with the sliding groove 302, a plurality of centering rods 303 are slidably mounted on the supporting cylinder 2, a connecting seat 304 is slidably mounted on the centering rods 303, a spring 305 is fixedly mounted on the connecting seat 304, the other end of the spring 305 is fixedly connected with the centering rods 303, a driving rod 306 is rotatably mounted on the driving ring 3, and the other end of the driving rod 306 is rotatably connected with the connecting seat 304. When the driving ring 3 rotates, the driving rods 306 on the driving ring 3 are driven to synchronously swing, the centering rods 303 are pushed to move towards the direction close to the pipeline by the synchronous swinging of the driving rods 306, and after the centering rods 303 are contacted with the pipeline, the centering of the pipeline can be completed, and the pipeline centering device can be suitable for pipelines with different diameters. When the centering rod 303 is in contact with the pipe, continued downward movement of the centering rod 303 compresses the spring 305, and pressure is applied to the pipe by the spring 305, preventing the centering rod 303 from directly applying pressure to the pipe, and preventing the pipe from being crushed.
As shown in fig. 3-5, fig. 7 and fig. 9-10, two centering mechanisms on two sides of the same supporting cylinder 2 are provided with spacing adjusting mechanisms, and the spacing adjusting mechanisms drive the pipeline to move inside the supporting cylinder 2. The distance between the two pipelines can be adjusted through the distance adjusting mechanism. The interval adjusting mechanism comprises a roller seat 6 fixedly arranged on centering rods 303 on centering mechanisms on two sides of a supporting cylinder 2, a roller 601 rotatably arranged on the roller seat 6, a first belt pulley 602 fixedly arranged on the roller 601, a second belt pulley 611 rotatably arranged on the centering rods 303, a transmission belt 603 arranged on the first belt pulley 602 and the second belt pulley 611, a gear 604 fixedly arranged on the second belt pulley 611, a supporting rod 609 fixedly arranged on the centering rods 303, a rack 610 slidably arranged on the supporting rod 609, wherein the rack 610 is meshed with the gear 604, a motor seat 605 is fixedly arranged on one centering rod 303, a first motor 606 is fixedly arranged on the motor seat 605, an internal threaded rod 607 is fixedly arranged on an output shaft of the first motor 606, a lead screw 608 is connected with the internal threaded rod 607, and the lead screw 608 is fixedly connected with the rack 610. When the centering rod 303 moves in the direction of approaching the pipe, the roller seat 6 is driven to move in the direction of approaching the pipe, so that the roller 601 contacts the pipe. And the pipeline is pressurized through the roller 601, so that a certain friction force exists between the roller 601 and the pipeline. When the pipeline is moved, the first motor 606 is started to drive the internal threaded rod 607 to rotate, the internal threaded rod 607 can drive the lead screw 608 to move, the lead screw 608 further drives the rack 610 to move, the moving rack 610 drives the gear 604 to rotate, the second belt pulley 611 is further driven to rotate, the first belt pulley 602 can be driven to rotate through the transmission of the transmission belt 603, the roller 601 is further driven to rotate, and the pipeline can be driven to move through friction between the roller 601 and the pipeline. And then carry out position control to the pipeline, and then can control the interval between two pipelines.
Further, since the pitch adjustment mechanism is mounted on the centering rod 303, the pitch adjustment mechanism moves with the movement of the centering rod 303, and thus can drive different pipes.
Still further, a linkage assembly is installed between the plurality of racks 610 on the same pitch adjustment mechanism, and the linkage assembly drives the plurality of racks 610 to move synchronously. The linkage assembly comprises a mounting block 7 fixedly mounted on the rack 610, two first connecting rods 701 rotatably mounted on the mounting block 7, and two second connecting rods 702 rotatably mounted on the first connecting rods 701, wherein the two adjacent second connecting rods 702 are mutually rotatably connected. When the centering rods 303 slide on the support cylinder 2, the racks 610 are driven to move, and the movement of the racks 610 drives the first connecting rod 701 and the second connecting rod 702 to turn over. Make first connecting rod 701 and second connecting rod 702 can carry out the automatic adaptation along with the position of rack 610, when one of them rack 610 moved, rack 610 would drive first connecting rod 701 and second connecting rod 702 and carry out synchronous motion, and then make a plurality of racks 610 carry out synchronous motion, and then make a plurality of gyro wheels 601 drive the pipeline simultaneously, thereby the driving force that makes the pipeline receive remains even, make the pipeline can steadily remove, and through the setting of a plurality of gyro wheels 601, can increase the area of contact of pipeline and interval adjustment mechanism, and then increase frictional force and driving force between pipeline and the interval adjustment mechanism.
As shown in fig. 6, a centering mechanism positioned in the middle of the same supporting cylinder 2 is provided with a fixing mechanism, and the fixing mechanism fixes the pipeline in the supporting cylinder 2. After the distance between the two pipelines is adjusted, the pipelines are further fixed through the fixing mechanism, and the pipelines are prevented from moving in the welding process. The fixing mechanism comprises a fastening pad 5 fixedly arranged on a centering rod 303 on a centering mechanism positioned in the middle of the supporting cylinder 2, the fastening pad 5 is made of a deformable rubber material, the fastening pad 5 is coated on a pipeline, and friction force is applied to the pipeline. The movement of the centering rod 303 will drive the tightening pad 5 to move, and after the tightening pad 5 is in contact with the pipe, the pipe is pressurized by the tightening pad 5 and is fixed by the friction between the tightening pad 5 and the pipe. And the fastening pad 5 is made of rubber material with a high friction coefficient. And the fastening pad 5 can take place certain deformation, can make the fastening pad 5 carry out the cladding to the pipeline, increase the frictional force between fastening pad 5 and the pipeline, and then can increase the fixed force of fastening pad 5 to the pipeline.
As shown in fig. 2 to 3, the first centering driving mechanism simultaneously drives the plurality of centering mechanisms connected to the pitch adjusting mechanism on the two support cylinders 2 to move. The first centering driving mechanism comprises first sector racks 307 fixedly arranged on driving rings 3 on two sides of the supporting cylinder 2, a first centering driving motor 309 fixedly arranged on the base 1, a first transmission shaft 310 fixedly arranged on the first centering driving motor 309, four first centering driving gears 308 fixedly arranged on the first transmission shaft 310, and the four first centering driving gears 308 are in one-to-one correspondence with the four first sector racks 307 and meshed with each other. The first driving shaft 310 can be driven to rotate by the first positioning driving motor 309, and the first driving shafts 310 can drive the plurality of first positioning driving gears 308 to rotate, so as to drive the first sector racks 307 to rotate. Thereby driving the driving ring 3 to rotate, and enabling the four driving rings to synchronously move, thereby ensuring the centering of the pipeline.
As shown in fig. 2-3, the second centering driving mechanism drives the centering mechanisms connected with the fixing mechanism on the two support cylinders 2 to move simultaneously. The second centering driving mechanism comprises a second centering driving motor 4 fixedly arranged on the base 1, a second transmission shaft 403 fixedly arranged on the second centering driving motor 4, a second centering driving gear 401 fixedly arranged on the second transmission shaft 403, and second sector racks 402 fixedly arranged on a driving ring 3 positioned in the middle on the supporting cylinder 2, wherein the two second sector racks 402 are in one-to-one correspondence with the two second centering driving gears 401 and are meshed with each other. When the pipeline is fixed, the second centering driving motor 4 is started to drive the second transmission shaft 403 to rotate, the second centering driving gear 401 is further driven to rotate, the second fan-shaped rack 402 is driven to rotate through the second centering driving gear 401, and accordingly the two driving rings 3 connected with the fixing mechanism are driven to rotate, and the centering mechanism can be driven to move.
The working principle is that after the limit rod 8 is rotated to move the nut 801 to a position coaxial with the limit hole, the nut 801 is inserted into the limit hole, and the limit rod 8 is used for plugging the support cylinder 2. The pipe is then inserted into the interior of the support cylinder 2 and the end of the pipe to be welded is brought to bear against the stop lever 8. The first driving shaft 310 is driven to rotate by the first positioning driving motor 309, and the first driving shafts 310 can drive the plurality of first positioning driving gears 308 to rotate, so as to drive the first sector racks 307 to rotate. Thereby driving the driving ring 3 to rotate, the driving rods 306 on the driving ring 3 are driven to synchronously swing, and the synchronous swing of the driving rods 306 pushes the centering rod 303 to move towards the direction approaching the pipeline. The roller seat 6 is driven to move in a direction approaching the pipeline, so that the roller 601 contacts the pipeline. And the pipeline is pressurized through the roller 601, so that a certain friction force exists between the roller 601 and the pipeline. The nut 801 is then removed from the limiting aperture and the limiting rod 8 is rotated so as not to obscure the support cylinder 2. Then start first motor 606 and drive internally threaded rod 607 and rotate, and then make lead screw 608 drive rack 610 and remove, rack 610 will drive first connecting rod 701 and second connecting rod 702 and remove in step, and then make a plurality of racks 610 remove in step, and then drive second band pulley 611 and rotate, can make first band pulley 602 rotate through the transmission of drive belt 603, and then make gyro wheel 601 rotate, can drive the pipeline through the frictional force between gyro wheel 601 and the pipeline and remove. And then carry out position control to the pipeline, and then can control the interval between two pipelines. After the position is adjusted, the second centering driving motor 4 is started to drive the second transmission shaft 403 to rotate, so that the two driving rings 3 connected with the fixing mechanism are driven to rotate, and the centering mechanism can be driven to move. The movement of the centering rod 303 will drive the tightening pad 5 to move, and after the tightening pad 5 is in contact with the pipe, the pipe is pressurized by the tightening pad 5 and is fixed by the friction between the tightening pad 5 and the pipe. And after the fixing is finished, the pipeline can be welded.
Example two
As shown in fig. 8, based on embodiment 1, a welding gun 910 rotatably installed between two support cylinders 2 is further included. The two pipes are welded by a welding gun 910. The welding gun seat 9 is fixedly arranged on the supporting cylinder 2, the slide way 901 is arranged on the welding gun seat 9, the rotating block 902 is slidably arranged on the slide way 901, the welding gun 910 is slidably arranged on the rotating block 902, the second motor 907 is slidably arranged on one welding gun seat 9, the welding driving gear 908 is slidably arranged on the other welding gun seat 9, the toothed ring 909 is fixedly arranged on the welding driving gear 908, and the welding driving gear 908 is rotationally connected with the rotating block 902. The output shaft of the second motor 907 is fixedly connected coaxially with the welding drive gear 908, and the welding drive gear 908 is intermeshed with the ring gear 909. When welding is performed, the welding gun 910 is slid, after the distance between the welding gun 910 and the pipeline is adjusted to a proper position, the welding gun 910 is started, and the second motor 907 is started to drive the welding driving gear 908 to rotate, so that the second welding driving gear 908 rotates along the toothed ring 909, and further the rotating block 902 is driven to slide along the slide 901, so that the welding gun 910 is driven to perform circular motion with the axis of the pipeline as the center, and further the pipeline is welded.
Two sliding rods 903 are fixedly arranged on the rotating block 902, a supporting plate 905 is slidably arranged on the sliding rods 903, two lifting screw rods 904 are rotatably arranged on the rotating block 902, the supporting plate 905 is in threaded connection with the lifting screw rods 904, and a linkage belt 906 is arranged on the two lifting screw rods 904. Rotating one of the lift screws 904 can enable the two lift screws 904 to synchronously rotate through the transmission of the linkage belt 906. The support plate 905 can be driven to move up and down through the rotation of the lifting screw 904, the welding gun 910 is fixedly connected with the support plate 905, the welding gun 910 can be driven to adjust, and the distance between the welding gun 910 and a pipeline can be adjusted.
The working principle is that one lifting screw rod 904 is rotated, and the two lifting screw rods 904 can synchronously rotate through the transmission of the linkage belt 906. The support plate 905 can be driven to move up and down through the rotation of the lifting screw 904, the welding gun 910 is fixedly connected with the support plate 905, the welding gun 910 can be driven to adjust, and the distance between the welding gun 910 and a pipeline can be adjusted. After the welding gun 910 is adjusted to a proper position, the second motor 907 is started to drive the welding driving gear 908 to rotate, so that the second welding driving gear 908 rotates along the toothed ring 909, and then the rotating block 902 is driven to slide along the slide 901, so that the welding gun 910 is driven to perform circular motion with the axis of the pipeline as the center, and further the welding operation is performed on the pipeline.
The above-described embodiments are merely a few alternative embodiments of the present invention, and many alternative modifications and combinations of the above-described embodiments will be apparent to those skilled in the art based on the technical solutions of the present invention and the related teachings of the above-described embodiments.