CN112833847B

CN112833847B - Chuck horizontal type edge turning test all-in-one machine

Info

Publication number: CN112833847B
Application number: CN202110091352.2A
Authority: CN
Inventors: 石守云; 沈正山; 尹亚英
Original assignee: Suzhou Swtek Prectse Machinery Co ltd
Current assignee: Suzhou Swtek Prectse Machinery Co ltd
Priority date: 2021-01-23
Filing date: 2021-01-23
Publication date: 2022-07-26
Anticipated expiration: 2041-01-23
Also published as: CN112833847A

Abstract

The utility model relates to a chuck production check out test set technical field especially relates to a horizontal car limit of chuck test all-in-one, it has the manual work to carry out the car limit processing to the chuck to aim at solving prior art, the roughness that leads to the car limit is difficult to obtain guaranteeing with the straightness that hangs down, finally lead to the defect that product quality descends, its technical scheme is a horizontal car limit of chuck test all-in-one, which comprises a frame, be equipped with in the frame and be used for carrying out the car limit module of lathe work to the chuck, be used for carrying out the test module of testing to the shell roughness of chuck and be used for carrying out the mould of carving characters of sign processing to the chuck, this application has the processingquality who guarantees the chuck product, improves the machining precision of the mechanical equipment who uses the chuck, improves the detection efficiency's of chuck quality effect simultaneously.

Description

Chuck horizontal type integrated machine for turning edge test

Technical Field

The application relates to the technical field of chuck production and detection equipment, in particular to a horizontal type integrated machine for testing the edge of a chuck.

Background

With the continuous increase of the mechanization degree of industrial production in China, the common quantity of the milling machine is higher and higher. The collet, known as collet or collet, is a barrel-type clamp for fastening a drill or milling cutter, and a fixing device for fixing and reinforcing a part to be modified, which is mounted on a milling machine. The chuck is widely applied to industrial production due to the advantages of convenient locking and the like.

The chuck is mainly used for clamping a drill bit to drill, and referring to fig. 1, the chuck comprises a main body 7 and a head 8, a core rod 9 for auxiliary testing is inserted in the center of the head 8, the chuck is difficult to machine, the process is complex, and the precision requirement is high, so that the machining process level of the chuck directly influences the performance and the product quality of the chuck. In the production process of the chuck, in order to be suitable for clamping workpieces of different specifications, a certain amount of residual materials are usually reserved at one end of the chuck, so that a worker can conveniently adjust and process the chuck according to actual use requirements.

The existing chuck edge turning mode usually adopts a machine to carry out edge turning processing, and then the flatness and the verticality of the chuck subjected to edge turning processing are manually processed.

Aiming at the related technologies, the inventor thinks that the defects that the flatness and the verticality of the edge turning are difficult to ensure and the quality of the product is reduced because the edge turning processing is carried out on the chuck manually exist.

Disclosure of Invention

In order to guarantee the processingquality of chuck product, improve the machining precision of the mechanical equipment who uses the chuck, improve the detection efficiency of chuck quality simultaneously, this application provides a horizontal car limit test all-in-one of chuck.

The application provides a horizontal car limit test all-in-one of chuck adopts following technical scheme:

the utility model provides a horizontal car limit test all-in-one of chuck, includes the frame, be equipped with in the frame and be used for carrying out lathe work to the chuck car limit module, be used for carrying out the test module that tests the shell roughness of chuck and be used for carrying out the module of carving characters of the sign processing of carving characters to the chuck.

Through adopting above-mentioned technical scheme, the car limit module is turned the part of reserving the surplus on the chuck, test module detects the roughness and the straightness that hangs down of chuck after the chuck turning is accomplished, detect and carry out the sign of carving characters to the work piece after accomplishing, the staff of being convenient for distinguishes the chuck, the quality of chuck product has been improved, the transfer distance between each process of chuck processing has been shortened simultaneously, the machining efficiency of the detection of chuck is carved characters has been improved, the staff of being convenient for detects the chuck, the quality of chuck product has finally been improved.

Optionally, the edge turning module comprises a fixing device for clamping the edge-to-be-turned chuck;

fixing device is including installing the take-up cylinder in the frame, be equipped with on the take-up cylinder with the coaxial pull rod and the hollow main shaft that set up of take-up cylinder's output shaft, the pull rod runs through the main shaft and stretches out outside the main shaft, the one end that take-up cylinder was kept away from to the pull rod is equipped with the locking subassembly that is used for the locking chuck, the locking subassembly sets up the elastic clamping jaw that distributes along the circumferencial direction of pull rod for a plurality of, the external diameter of elastic clamping jaw is greater than the internal diameter of main shaft.

By adopting the technical scheme, the tensioning cylinder enables the locking assembly to be contracted in the main shaft through the pull rod, so that the elastic clamping jaw in the locking assembly is contracted towards the center under the limitation of the main shaft to finally tighten the locking chuck, the chuck is fixed in a contraction clamping manner, the possibility of loosening the chuck is reduced, the fixing stability in the process of turning the chuck is ensured, the possibility of deviation of the chuck is reduced, and the quality of a chuck product is improved; meanwhile, the elastic clamping jaws with elasticity are adopted in the locking assembly to fix the chuck, so that the possibility of damage in the process of fixing the chuck is reduced.

Optionally, the pull rod is connected with the output shaft of the tensioning cylinder in a coaxial rotating mode, a belt pulley is arranged on the peripheral wall of the main shaft, a rotating motor is arranged on the rack, a transmission belt is arranged on the output shaft of the rotating motor, and the transmission belt drives the main shaft to rotate through the belt pulley.

By adopting the technical scheme, the main shaft is driven to rotate by the rotating motor through the matching relation between the transmission belt and the belt pulley, so that the surface of the chuck can be turned uniformly, the surface flatness of the chuck is improved, the pull rod is rotationally connected with the output end of the tensioning cylinder, the pull rod is not influenced in the rotating process of the main shaft, the transmission belt is adopted for transmission, the transmission relation between the rotating motor and the main shaft is ensured when the main shaft moves, and the stability of a transmission system is improved.

Optionally, still be equipped with the positioner who is used for fixing a position the chuck in the frame, positioner is including installing the location cylinder in the frame, the central axis direction setting along the pull rod of the output shaft of location cylinder, be fixed with the location slider with the coaxial setting of output shaft of location cylinder on the output shaft of location cylinder, the one end of keeping away from the location cylinder on the slider of location is equipped with the mounting panel, the one end of keeping away from the location slider on the mounting panel is equipped with the holding ring that is used for fixing a position the chuck.

Through adopting above-mentioned technical scheme, adopt positioner to fix the position of chuck, fixity when having guaranteed the chuck turning has reduced the chuck because of the lathe tool that receives when the turning power the possibility that the skew takes place for the power of exerting, and then has improved the product quality of chuck, adopts the location cylinder to drive the position of holding ring, when the chuck removed, makes the holding ring remove according to the position of chuck, has guaranteed the fixed effect of holding ring.

Optionally, a positioning sliding seat used for being matched with the positioning sliding block is fixedly mounted on the frame, and the positioning sliding seat is arranged along the direction of the output shaft of the positioning cylinder; and a positioning reinforcing plate for supporting the mounting plate is arranged between the positioning sliding block and the mounting plate.

By adopting the technical scheme, the positioning slide seat is adopted to limit the orientation of the positioning slide block, so that the stability of the positioning slide block during movement is improved, the fixity of the positioning direction of the positioning ring fixed on the positioning slide block is ensured, and the possibility of deviation of the positioning slide block during movement is reduced; the positioning reinforcing plate arranged between the positioning sliding block and the mounting plate supports and fixes the mounting plate, so that the possibility of deviation of the positioning ring when stressed is reduced, and the positioning stability of the positioning ring is enhanced.

Optionally, the turning module further includes a turning device for performing turning, the turning device includes an installation seat disposed on the frame, the bottom of the installation seat is provided with a plurality of first sliding blocks, and the frame is provided with a first sliding rail disposed along a central axis direction of the pull rod; a second slide rail is arranged on the mounting seat along the direction vertical to the first slide rail, and a turning tool for turning a chuck is slidably mounted on the second slide rail; and the turning tool is also provided with an air blowing head for blowing the chuck.

By adopting the technical scheme, the first slide rail and the second slide rail which are perpendicular to each other are matched, so that the turning tool can be fixed at any position in a use range, the processing of chucks of different specifications is facilitated, and the use flexibility of the turning tool is improved; the blowing head arranged on one side of the turning tool blows the contact turning positions of the chuck and the turning tool, so that residual scrap iron on the chuck can be cleaned conveniently, the turning tool can be maintained to accurately process the chuck conveniently, and finally the product quality of the chuck is improved.

Optionally, the test module includes a test motor installed on the frame, a mounting hole for fixing the chuck is formed in an output shaft of the test motor, the mounting hole is formed in the direction of the output shaft of the test motor, the test module further includes a meter-punching probe installed on the frame, and the meter-punching probe is provided with a plurality of probes in the frame.

Through adopting above-mentioned technical scheme, the chuck is installed on the output shaft of test motor, it is rotatory that test motor drive chuck, the rotatory in-process of chuck is beaten the table probe and is contradicted to the chuck, when the chuck is rotatory, if the probe takes place the displacement of beating the table on the chuck of chuck outer wall unevenness then, thereby take notes the roughness on chuck surface, adopt a plurality of to beat the table probe and test the chuck simultaneously, improved the degree of accuracy of test, reduced the test result and taken place to miss the possibility of surveying, mistake finding.

Optionally, the lettering module comprises a chuck placing device and a pneumatic marking machine, wherein the chuck placing device and the pneumatic marking machine are installed on the rack, and the chuck placing device is arranged below the pneumatic marking machine.

Through adopting above-mentioned technical scheme, chuck placer fixes the chuck, and pneumatic marking machine carries out mark up to standard to the chuck, has improved the recognition efficiency of staff to the chuck, is convenient for distinguish and select the chuck, adopts pneumatic marking machine to carry out the sign to the chuck, has reduced the impaired possibility of in-process chuck of beating mark carving characters, has improved the quality of chuck product.

Optionally, still install the defective products collection device who is used for placing the chuck defective products in the frame, defective products collection device is including placing the board, it has a plurality of projection that is used for fixed chuck defective products to place evenly distributed on the board, the one end of keeping away from on the projection and placing the board is equipped with the direction inclined plane that is used for guiding the chuck.

Through adopting above-mentioned technical scheme, defective products collection device collects the defective products in the chuck, and the staff of being convenient for sieves the defective products in the chuck according to the testing result of test module, has reduced the possibility that the defective products appears in the chuck finished product, and the guide inclined plane guides the chuck, and the probability that the defective products appears in the chuck of being convenient for reduces, and then has guaranteed the quality of chuck product.

Optionally, the car limit module dustcoat is equipped with the dust cover that is used for isolated iron fillings.

Through adopting above-mentioned technical scheme, the dust cover is cleaned the iron fillings that produce through the turning on the chuck, has reduced the possibility of remaining iron fillings on the chuck, and then has guaranteed the machining precision of lathe tool, has improved the product quality of chuck.

In summary, the present application includes at least one of the following beneficial technical effects:

1. the edge turning module turns the part reserved with allowance on the chuck, the testing module detects the flatness and the verticality of the chuck after the chuck turning is finished, and marks are engraved on a workpiece after the detection is finished, so that workers can distinguish the chuck conveniently, the quality of a chuck product is improved, the transfer distance between all working procedures of chuck processing is shortened, the processing efficiency of the chuck for detecting and engraving is improved, the workers can conveniently detect the chuck, and the quality of the chuck product is finally improved;

2. the first slide rail and the second slide rail which are vertically arranged are matched, so that the turning tool can be fixed at any position in a use range, the processing of chucks of different specifications is facilitated, and the use flexibility of the turning tool is improved; the blowing head arranged on one side of the turning tool blows the contact turning positions of the chuck and the turning tool, so that residual scrap iron on the chuck can be cleaned conveniently, the accurate processing of the chuck by the turning tool can be maintained conveniently, and the product quality of the chuck is improved finally;

3. chuck placer fixes the chuck, and pneumatic marking machine carries out mark up to standard to the chuck, has improved the recognition efficiency of staff to the chuck, is convenient for distinguish and select the chuck, adopts pneumatic marking machine to carry out the sign to the chuck, has reduced and has beaten the impaired possibility of in-process chuck of beating mark carving characters, has improved the quality of chuck product.

Drawings

FIG. 1 is a schematic view of a chuck in the present application;

FIG. 2 is a schematic overall structure diagram of a horizontal type chuck edge turning test all-in-one machine shown in the embodiment of the application;

fig. 3 is a schematic structural diagram of a vehicle edge module of the chuck horizontal vehicle edge testing all-in-one machine shown in the embodiment of the application;

FIG. 4 is an exploded view of a fixture of a horizontal cartridge edge testing machine shown in an embodiment of the present application;

fig. 5 is a schematic structural diagram of a test module of the horizontal chuck type integrated edge-turning test machine shown in the embodiment of the present application;

FIG. 6 is a schematic structural diagram of a lettering module of the horizontal chuck type integrated edge turning test machine shown in the embodiment of the application;

fig. 7 is a schematic structural diagram of a defective product collecting device of a horizontal type integrated machine for testing a car edge of a chuck in the embodiment of the application.

Description of the reference numerals: 1. a frame; 2. turning a side module; 21. a fixing device; 211. tensioning the cylinder; 212. a pull rod; 213. a main shaft; 214. a locking assembly; 2141. an elastic clamping jaw; 22. a positioning device; 221. positioning the air cylinder; 222. positioning the sliding block; 223. mounting a plate; 224. a positioning ring; 225. positioning a sliding seat; 226. positioning the reinforcing plate; 23. turning a device; 231. a mounting base; 232. a first slider; 233. a first slide rail; 234. a second slide rail; 235. turning a tool; 236. a blowing head; 24. a belt pulley; 25. rotating the motor; 26. a drive belt; 3. a test module; 31. testing the motor; 32. mounting holes; 33. a probe is marked; 4. a lettering module; 41. a chuck placing device; 42. a pneumatic marking machine; 5. a defective product collection device; 51. placing a plate; 52. a convex column; 53. a guide slope; 6. a dust cover; 7. a main body; 8. a head portion; 9. and (4) a core rod.

Detailed Description

The present application is described in further detail below with reference to figures 1-7.

The embodiment is as follows:

the embodiment of the application discloses horizontal car of chuck limit test all-in-one.

Referring to fig. 1, the collet comprises a cylindrical body 7, one end of the body 7 is provided with a head 8 having a conical shape, and a core rod 9 extending into the body 7 is inserted in the center of the head 8.

Referring to fig. 2, a horizontal car of chuck test all-in-one, including frame 1, install the car limit module 2 that is used for carrying out lathe work to the chuck in the frame 1, be used for carrying out the test module 3 that the roughness detected to the chuck, be used for carrying out the mould 4 of carving characters that the sign was distinguished and be used for carrying out the defective products collection device 5 that collects to the defective products chuck that detects out, car limit module 2 upper shield is equipped with the dust cover 6 that is used for keeping apart the iron fillings that the turning produced, defective products collection device 5 locates the top of dust cover 6.

With reference to fig. 3 and 4, the edging module 2 comprises a fixing device 21 for fixing the collet, a positioning device 22 for auxiliary positioning of the collet and a turning device 23 for turning the collet. The turning device 23 includes a first slide rail 233 installed on the frame 1, a mounting seat 231 is installed on the first slide rail 233 in a sliding manner, four first slide blocks 232 are arranged at the bottom of the mounting seat 231, the mounting plate 223 slides on the first slide rail 233 through the first slide blocks 232, a second slide rail 234 which is perpendicular to the direction of the first slide rail 233 is arranged on the mounting seat 231, a turning tool 235 which is used for performing edge turning processing on a chuck is installed on the second slide rail 234 in a sliding manner, and a blowing head 236 which is installed on the second slide rail 234 is further arranged on one side of the turning tool 235.

Referring to fig. 3 and 4, the fixing device 21 includes a tensioning cylinder 211 installed in the frame 1, a pull rod 212 coaxially disposed with an output shaft of the tensioning cylinder 211 is disposed on an output shaft of the tensioning cylinder 211, the pull rod 212 is coaxially and rotatably connected with the output shaft of the tensioning cylinder 211 through a bearing, a locking assembly 214 for locking the chuck is disposed at an end of the pull rod 212 far away from the tensioning cylinder 211, the locking assembly 214 includes three elastic clamping jaws 2141 uniformly distributed along a circumferential direction of the pull rod 212 on an end surface of the pull rod 212, the three elastic clamping jaws 2141 are centrosymmetrically distributed with a center of the pull rod 212 as a center of symmetry, and a groove for placing the mandrel 9 on the chuck is disposed at a center of the three elastic clamping jaws 2141. The outer circumferential walls of the three elastic clamping jaws 2141 are outwardly inclined and expanded, the pull rod 212 is sleeved with the main shaft 213 for accommodating the pull rod 212, and the inner diameter of the main shaft 213 is smaller than the outer diameter formed by combining the three elastic clamping jaws 2141, so that when the pull rod 212 contracts, the main shaft 213 applies a pressure to the elastic clamping jaws 2141 to contract the elastic clamping jaws, and the chuck is fixed.

Referring to fig. 3 and 4, the main shaft 213 is mounted on the frame 1 through a bearing, the main shaft 213 is provided with a belt pulley 24 arranged along a circumferential direction thereof, the frame 1 is provided with a rotating motor 25 for driving the main shaft 213 to rotate, a transmission belt 26 is mounted between an output shaft of the rotating motor 25 and the belt pulley 24, and the rotating motor 25 drives the main shaft 213 through the transmission belt 26, so as to drive the main shaft 213 to rotate. The positioning device 22 includes a positioning cylinder 221 mounted on the frame 1, an output end of the positioning cylinder 221 is disposed along a central axis direction of the pull rod 212, a positioning slider 222 is fixed to an output end of the positioning cylinder 221, a positioning slide 225 for guiding a sliding direction of the positioning slider 222 is further mounted on the frame 1, and a direction of the positioning slide 225 is the same as an extending direction of the output end of the cylinder. A mounting plate 223 is vertically arranged at one end of the positioning slider 222 away from the positioning cylinder 221, a positioning ring 224 for fixing the collet is fixed at the lower end of the mounting plate 223, and the inner diameter of the positioning ring 224 is the same as the diameter of the mandrel 9. A triangular positioning reinforcing plate 226 is installed between the mounting plate 223 and the positioning slider 222, so as to support and protect the mounting plate 223.

Referring to fig. 5, test module 3 is including being used for driving the rotatory test motor 31 of chuck, test motor 31 installs in frame 1, offer the mounting hole 32 that is used for the plug 9 of fixed chuck on test motor 31's the output shaft, the central axis direction setting of test motor 31's output shaft is followed to mounting hole 32, test module 3 still includes three parallel arrangement's probe 33 that beats, the output of probe 33 that beats conflicts on the chuck, be convenient for detect the beating when rotatory to the chuck, the staff of being convenient for detects the surface smoothness information that obtains the chuck.

Referring to fig. 6, the lettering module 4 includes a chuck placing device 41 and a pneumatic marking machine 42 for lettering, the chuck placing device 41 is disposed below the pneumatic marking machine 42, and the chuck placing device 41 is configured as a two-jaw chuck with jaws matched with the chucks.

Referring to fig. 7, defective products collection device 5 is including placing board 51, places and is equipped with a plurality of lug 52 that is used for fixed chuck defective products on board 51, is equipped with the direction inclined plane 53 that is used for guiding the chuck on the periphery wall of lug 52, and lug 52 is uneven distribution on placing board 51, is convenient for collect the chuck of different bad grades according to the difference that lug 52 distributes and places, is convenient for improve the recovery and use efficiency of chuck.

The implementation principle of the horizontal type vehicle-side testing integrated machine for the chuck in the embodiment of the application is as follows: when the chuck needs to be machined, the chuck is placed between the elastic clamping jaws 2141 of the locking assembly 214, the tensioning cylinder 211 is started, the tensioning cylinder 211 pulls the pull rod 212, the elastic clamping jaws 2141 contract, the chuck is fixed, the positioning device 22 plays a positioning role for the chuck, and the turning device 23 performs edge turning on the chuck after the chuck is fixed. After the processing is finished, the chuck is installed in the installation hole 32 on the output shaft of the testing motor 31, the meter-punching probe 33 is adjusted to enable the meter-punching probe 33 to abut against the chuck, the testing motor 31 is started to test the chuck, the chuck is marked with characters after a testing result is obtained, and defective products are placed on the defective product collecting device 5 to be collected.

The above are preferred embodiments of the present application, and the scope of protection of the present application is not limited thereto, so: equivalent changes in structure, shape and principle of the present application shall be covered by the protection scope of the present application.

Claims

1. The utility model provides a horizontal car limit test all-in-one of chuck which characterized in that: the clamp comprises a rack (1), wherein a turning edge module (2) for turning a chuck, a testing module (3) for testing the flatness of a shell of the chuck and a lettering module (4) for lettering and marking the chuck are arranged on the rack (1); the edge turning module (2) comprises a fixing device (21) for clamping a to-be-turned edge clamping head; the fixing device (21) comprises a tensioning cylinder (211) installed on the frame (1), a pull rod (212) and a hollow main shaft (213) are arranged on the tensioning cylinder (211) and are coaxially arranged with an output shaft of the tensioning cylinder (211), the pull rod (212) penetrates through the main shaft (213) and extends out of the main shaft (213), a locking assembly (214) used for locking a chuck is arranged at one end, away from the tensioning cylinder (211), of the pull rod (212), the locking assembly (214) is provided with a plurality of elastic clamping jaws (2141) distributed along the circumferential direction of the pull rod (212), and the outer diameter of each elastic clamping jaw (2141) is larger than the inner diameter of the main shaft (213); the pull rod (212) is coaxially and rotatably connected with an output shaft of the tensioning cylinder (211), a belt pulley (24) is arranged on the peripheral wall of the main shaft (213), a rotating motor (25) is arranged on the rack (1), a transmission belt (26) is arranged on the output shaft of the rotating motor (25), and the transmission belt (26) drives the main shaft (213) to rotate through the belt pulley (24); the clamping head positioning device comprises a rack (1), and is characterized in that a positioning device (22) for positioning a clamping head is further arranged on the rack (1), the positioning device (22) comprises a positioning cylinder (221) arranged on the rack (1), an output shaft of the positioning cylinder (221) is arranged along the direction of the central axis of a pull rod (212), a positioning slider (222) coaxially arranged with the output shaft of the positioning cylinder (221) is fixed on the output shaft of the positioning cylinder (221), a mounting plate (223) is arranged at one end, far away from the positioning cylinder (221), of the positioning slider (222), and a positioning ring (224) for positioning the clamping head is arranged at one end, far away from the positioning slider (222), of the mounting plate (223); a positioning sliding seat (225) matched with the positioning sliding block (222) is fixedly arranged on the rack (1), and the positioning sliding seat (225) is arranged along the direction of an output shaft of the positioning cylinder (221); a positioning reinforcing plate (226) used for supporting the mounting plate (223) is arranged between the positioning sliding block (222) and the mounting plate (223); the turning edge module (2) further comprises a turning device (23) for turning, the turning device (23) comprises a mounting seat (231) arranged on the rack (1), the bottom of the mounting seat (231) is provided with a plurality of first sliding blocks (232), and the rack (1) is provided with a first sliding rail (233) arranged along the direction of the central axis of the pull rod (212); a second slide rail (234) is arranged on the mounting seat (231) along a direction perpendicular to the first slide rail (233), and a turning tool (235) for turning the chuck is slidably mounted on the second slide rail (234); the turning tool (235) is also provided with a blowing head (236) for blowing the chuck; the testing module (3) comprises a testing motor (31) arranged on the rack (1), an output shaft of the testing motor (31) is provided with a mounting hole (32) for fixing a chuck, the mounting hole (32) is arranged along the direction of the output shaft of the testing motor (31), the testing module (3) further comprises a plurality of meter-reading probes (33) arranged on the rack (1), and the meter-reading probes (33) are arranged on the rack (1); the lettering module (4) comprises a chuck placing device (41) and a pneumatic marking machine (42) which are arranged on the rack (1), wherein the chuck placing device (41) is arranged below the pneumatic marking machine (42).

2. The horizontal type integrated machine for testing the edge of the chuck as claimed in claim 1, which is characterized in that: still install defective products collection device (5) that are used for placing the chuck defective products on frame (1), defective products collection device (5) is including placing board (51), it has a plurality of to be used for fixing lug boss (52) of chuck defective products to place evenly distributed on board (51), keep away from the one end of placing board (51) on lug boss (52) and be equipped with direction inclined plane (53) that are used for guiding the chuck.

3. The horizontal type integrated machine for testing the edge of the chuck as claimed in claim 1, which is characterized in that: and a dust cover (6) for isolating scrap iron is arranged on the outer cover of the edge turning module (2).