CN209866983U

CN209866983U - Turning device of calender for aluminum coil processing

Info

Publication number: CN209866983U
Application number: CN201920084553.8U
Authority: CN
Inventors: 李文智
Original assignee: Zhongkai Da (tianjin) Science And Technology Development Co Ltd
Current assignee: Zhongkai Da (tianjin) Science And Technology Development Co Ltd
Priority date: 2019-01-18
Filing date: 2019-01-18
Publication date: 2019-12-31
Anticipated expiration: 2029-01-18

Abstract

The utility model discloses a turning device of a calender for processing aluminum coils, which comprises a main body, wherein the main body comprises a fixed cover and a sliding cover sleeved outside the fixed cover, the sliding cover is sleeved with a limit cover welded and fixed with the fixed cover, the sliding cover is connected with the fixed cover in a sliding way, the equipment is provided with a material limit frame which can limit the turned material, the material can be limited by a first flattening plate and a pre-pressing flat frame when passing through the material limit frame, even if the material is turned by the turning fixing frame, the position of the material can not be driven, the position can not be shifted when the material is sent out, so that the equipment can carry out turning operation and limit the material, and the situation that the material is blocked after being rolled by the obliquely sent material can be avoided, the market competitiveness of more functions is higher, and the second flattening plate is also provided with a limit fixture block of a bottom connecting rod, the materials with different sizes can be limited, and the application range is wide and the practicability is strong.

Description

Turning device of calender for aluminum coil processing

Technical Field

The utility model relates to an aluminium is rolled up and is processed technical field, specifically is an aluminium is rolled up turning device of processing with calender.

Background

For rolling of aluminum coils, strips with different thicknesses and widths can be rolled according to the requirements of customers. In the process of rolling thick materials and narrow materials, the roll gap of the roll cannot be closed, particularly the roll gap of the thick materials is larger, rolling oil can reach the outlet side of a rolling mill from the edge gap of a strip and adhere to the surface of the strip, the product quality is influenced, and the treatment difficulty of the subsequent process is increased. For thin aluminum coils this can be achieved by a calendering process.

The calender is a machine which is arranged by two or more than two rollers according to a certain form, presses and stretches rubber or plastics into a film with a certain thickness and a certain surface shape at a certain temperature, and can glue the fiber curtain canvas or the steel cord fabric, but once the material is twisted and folded when being fed into the equipment, the material generates a large amount of waste materials after calendering, so that a user usually uses a turnover device to ensure that the material fed into the calender cannot be bent in order to avoid the generation of the waste materials.

The common calender turning devices in the current market generally face that most turning devices are simple in structure and only have a turning function, so that the market competitiveness of equipment is low, and meanwhile, most materials are extremely prone to deviation after being turned, and then the materials are fed into a calender to be rolled and delayed to easily generate a blocking phenomenon, so that the subsequent operation is influenced, and the practicability is not high;

and most of turning devices only have the function of once overturning, and some materials are very easily kick-backed and tilted after being overturned because the curling time is longer, so that subsequent normal operation is influenced, and the practicability is not strong.

Disclosure of Invention

In order to overcome the not enough of prior art scheme, the utility model provides an aluminium is rolled up turning device of processing with calender can the effectual problem that solves the background art and provide.

The utility model provides a technical scheme that its technical problem adopted is: the turning device of the calender for processing the aluminum coil comprises a main body, wherein the main body comprises a fixed cover and a sliding cover sleeved outside the fixed cover, a limiting cover welded and fixed with the fixed cover is sleeved outside the sliding cover, the sliding cover is connected with the fixed cover in a sliding mode, a lead screw fixing groove for internally mounting a driving lead screw is formed in the inner wall of the upper portion of the fixed cover, the left side of the driving lead screw is connected with a driving motor, a sliding sleeve for internally mounting a spring is sleeved outside the driving lead screw, a pre-pressing flat frame is mounted below the spring, a material limiting frame is mounted below the pre-pressing flat frame, a first roller and a second roller are mounted on the left side of the pre-pressing flat frame, and two second rollers which are symmetrical up and down about the central axis of the fixed cover are mounted on the right side of the pre-;

the prepressing flat frame comprises a fixed support frame and a plurality of connecting columns connected with the fixed support frame through screws, a plurality of heating blocks with heating resistance wires arranged inside are sleeved outside the connecting columns, and auxiliary flattening sleeves connected with the heating blocks in a sliding mode are sleeved outside the heating blocks;

the material limiting frame comprises a first pressing plate and a second pressing plate, wherein a pressing sleeve through hole is formed in the upper surface of the first pressing plate, the first pressing plate is connected with the second pressing plate in a clamping mode, a sliding limiting clamping groove is formed in the inner wall of the upper portion of the second pressing plate, a limiting clamping block is placed in the sliding limiting clamping groove, the left side and the right side of the lower surface of the second pressing plate are provided with two supporting covers which are symmetrical with respect to the central axis of the second pressing plate, springs are installed in the two supporting covers, the bottom of the limiting clamping block is connected with a connecting rod, an electric push rod is installed below the connecting rod in a rotating mode, connecting rod supporting blocks are arranged on the left side and the right side of the connecting rod and connected with the connecting rod in a rotating mode through rotating shafts, the connecting rod is connected.

As a preferred technical proposal of the utility model, the right side of the sliding cover is rotationally connected with a second sliding cover, the second sliding cover is provided with a fixture block fixing groove for placing a sliding fixture block inside, the right side of the second sliding cover is provided with a turnover fixing frame for installing a turnover fixing wheel inside, the side wall of the turnover fixing wheel is provided with a spring, one side of the sliding fixture block close to the turnover fixing wheel is provided with a flattening frame for installing a rebound-proof press block inside, the side wall of the rebound-proof press block is provided with a spring, the sliding fixture block is provided with a rotating connecting frame for installing a sliding fixture sleeve on the side wall on the side far away from the turnover fixing wheel, the right side of the sliding cover is fixedly welded with a clamping cover, the upper side wall of the clamping cover is provided with a driving motor for connecting the right side, and the lower inner wall of the clamping cover is provided with a cam fixing, the cam fixing cover is internally provided with a cylindrical cam which is rotationally connected with the cam fixing cover, and the side wall of the cylindrical cam is provided with a straight rod which is slidably connected with the sliding clamping sleeve.

As an optimized technical scheme of the utility model, the lateral wall of second slip cap is provided with the rack with drive gear meshing.

As an optimal technical scheme, the lateral wall of slip cap is provided with the rack plate in the left side region of screens cover, be provided with the fixed fixture block recess of the spacing fixed fixture block of internally mounted material in the first gyro wheel, the extension spring is installed to the lateral wall of the spacing fixed fixture block of material.

As an optimal technical scheme, internally mounted rotating gear's gear fixing hole is seted up to spacing cover's top outer wall, rotating gear's top is provided with the driving motor who is connected through the belt pulley rotation with rotating gear.

Compared with the prior art, the beneficial effects of the utility model are that:

(1) the equipment is provided with a material limiting frame consisting of a first pressing plate and a second pressing plate, the material limiting frame can limit overturned materials, the materials can be limited by the first pressing plate and a pre-pressing flat frame when passing through the material limiting frame, even if the overturned fixing frame drives the materials to overturn, the positions of the materials cannot be driven, and the positions of the materials cannot be shifted when the materials are sent out, so that the equipment can carry out overturning operation and limit the materials, and the situation that the materials are blocked easily after being rolled by the obliquely sent materials is avoided;

(2) this equipment still is equipped with the upset mount and flattens the frame, and after the material was overturned through the upset mount, the user can make to flatten the frame and slide repeatedly on the material through rotating the cylinder cam drive straight-bar to the realization carries out the purpose of flattening in advance to the material, makes the material can not kick-back the perk easily, thereby has avoided follow-up operation to receive the condition emergence of influence.

Drawings

Fig. 1 is a schematic structural view of the present invention;

FIG. 2 is an external view of the present invention;

FIG. 3 is a right sectional view of the material limiting rack of the present invention when installed;

fig. 4 is a right partial sectional view of the present invention;

fig. 5 is a top cross-sectional view of the present invention;

fig. 6 is a front cross-sectional view of the pre-pressing flat frame of the present invention.

In the figure: 1-main body, 2-fixed cover, 3-sliding cover, 4-limit cover, 5-rack plate, 6-rotating gear, 7-overturn fixed frame, 8-position clamping cover, 9-driving gear, 10-lead screw fixed groove, 11-driving lead screw, 12-sliding sleeve, 13-first roller, 14-second roller, 15-material limit frame, 16-connecting rod supporting block, 17-electric push rod, 18-supporting cover, 19-cylindrical cam, 20-cam fixed cover, 21-rotating connecting frame, 22-fixture block fixed groove, 23-sliding fixture block, 24-flattening frame, 25-rebound prevention press block and 26-overturn fixed wheel; 211-a sliding clamping sleeve, 61-a gear fixing through hole, 91-a rack, 121-a spring, 122-a pre-pressing flat frame, 1221-a fixing support frame, 1222-an auxiliary pressing flat sleeve, 1223-a heating block, 1224-a connecting column, 131-a material limiting fixing clamping block, 132-a fixing clamping block groove 132, and 133-a tension spring; 151-a first pressing plate, 152-a second pressing plate, 153-a connecting rod, 154-a sliding limit clamping groove and 155-a limit clamping block.

Detailed Description

The technical solutions in the embodiments of the present invention will be described clearly and completely with reference to the accompanying drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative work belong to the protection scope of the present invention.

As shown in figure 1, the utility model provides a turning device of calender for aluminum coil processing, which comprises a main body 1, the main body 1 comprises a fixed cover 2 and a sliding cover 3 sleeved outside the fixed cover 2, the side wall of the fixed cover 2 is of a circular structure, the inner wall of the fixed cover is of a square structure, a material limiting frame 15 can not easily slide when in use, meanwhile, the fixed cover 2 can also play the role of assisting in fixing the material limiting frame 15, the sliding cover 3 can play the purpose of limiting the position of a turning fixing frame 7, so that the turning fixing frame 7 can also move after the sliding cover 3 is driven, the sliding cover 3 is sleeved with a limiting cover 4 welded and fixed with the fixed cover 2, the sliding cover 3 is connected with the fixed cover 2 in a sliding way, the limiting cover 4 plays the purpose of limiting the position of the sliding cover 3, so that the sliding cover 3 can not slide out when turning again, the upper inner wall of the fixed cover 2 is provided with a lead screw fixed groove 10 internally provided with a driving lead screw 11, the driving lead screw 11 can play a role in moving the position of a sliding sleeve 12, so that when a material is placed on a material limiting frame 15 for limiting, the sliding sleeve 12 and a pre-pressing flat frame 12 can be driven by the driving lead screw 11 to carry out secondary limiting on the material, and when the material is pulled by the outside, the pre-pressing flat frame 12 can also carry out pre-pressing flat operation on the material, the left side of the driving lead screw 11 is connected with a driving motor, the sliding sleeve 12 internally provided with a spring 121 is sleeved outside the driving lead screw 11, the position of the pre-pressing flat frame 122 of the sliding sleeve 12 can be micro-adjusted according to the thickness of the material due to the spring 121 arranged inside, so that the material cannot be pressed too hard when being thick, thereby avoiding the situation that the material is torn off when being pulled and moved, the pre-, a material limiting frame 15 is arranged below the pre-pressing flat frame 122, the material limiting frame 15 can limit materials, so that the positions of the turned materials cannot be greatly deviated, a first roller 13 and a second roller 14 are arranged on the left side of the pre-pressing flat frame 122, the first roller 13 and the second roller 14 can perform secondary limiting when the materials are transmitted, so that the positions of the materials are limited more stably, two second rollers 14 which are symmetrical up and down about the central axis of the fixed cover 2 are arranged on the right side of the pre-pressing flat frame 122, the second rollers 14 can perform auxiliary feeding and protecting functions, so that the materials cannot shake randomly when turned over, and the situation that the materials are scratched is avoided;

as shown in fig. 1 and 6, the pre-pressing flat frame 122 includes a fixed support 1221 and a plurality of connecting posts 1224 connected with the fixed support 1221 by screws, the fixed support 1221 is connected with the connecting posts 1224 by screws, so that the connecting posts 1224 are more convenient to disassemble and repair, a plurality of heating blocks 1223 with heating resistance wires arranged inside are sleeved outside the connecting posts 1224, the heating blocks 1223 can play a role of heating the auxiliary pressing sleeve 1222, so that the auxiliary pressing sleeve 1222 can pre-heat materials, so that the subsequent pressing delay efficiency is higher, when in operation, when materials are placed on the material limiting frame 15, a user can press the pre-pressing flat frame 122 on the surface of the materials, and simultaneously open the heating resistance wires in the heating blocks 1223, so that the auxiliary pressing sleeve 1222 is heated, and then pull the materials outside, so that the materials drive the auxiliary pressing sleeve 1222 to roll, the material is heated and softened, so that the subsequent calendering efficiency is higher, and an auxiliary flattening sleeve 1222 connected with the heating block 1223 in a sliding manner is sleeved outside the heating block 1223;

as shown in fig. 1, 3, 5 and 6, the material limiting frame 15 includes a first pressing plate 151 having a pressing sleeve through hole on an upper surface thereof and a second pressing plate 152 connected with the first pressing plate 151 in a clamping manner, the first pressing plate 151 can limit a material with a larger size, and when the material has a smaller size, a user can place the material on the second pressing plate 152 to achieve the purpose of limiting, a sliding limiting slot 154 having a limiting block 155 inside is formed on an upper inner wall of the second pressing plate 152, the limiting block 155 can clamp the material, when limiting, the limiting block 155 can slide in the sliding limiting slot 154, so as to achieve the purpose of limiting the material, the left and right sides of a lower surface of the second pressing plate 152 are provided with supporting covers 18 symmetrical with respect to a central axis of the second pressing plate 152, the supporting covers 18 are used for ensuring balance of the material limiting frame 15 when placing, the springs 121 are arranged in the support covers 18, so as to damp vibration of the equipment, so that the heating area of the auxiliary flattening sleeve 1222 is more uniform when the auxiliary flattening sleeve 1222 is heated, the situation that the material is vibrated and the auxiliary flattening sleeve 1222 is deeply pressed to cause a groove to appear on the surface of the material is avoided, two support covers 18 are arranged, the springs 121 are arranged in each of the two support covers 18, the bottom of the limiting fixture block 155 is rotatably connected with the connecting rod 153 below which the electric push rod 17 is arranged, the connecting rod 153 can control the position of the limiting fixture block 155, when a user operates the electric push rod 17 through an external controller to ascend, the electric push rod 17 can push the connecting rod 153 to ascend, and the connecting rod 153 can rotate around the rotating shaft on the connecting rod support block 16, so that the two limiting fixture blocks 155 slide in the direction away from each other, and once the electric push rod 17 descends, the connecting rod 153 can drive the two limiting fixture blocks 155, therefore, material limiting with different sizes is achieved, connecting rod supporting blocks 16 which are rotatably connected with the connecting rod 153 through a rotating shaft are arranged on the left side and the right side of the connecting rod 153, the connecting rod 153 is connected with the electric push rod 17 through screws, the electric push rod 17 which is connected with the second pressing plate 152 through screws is arranged on the right side of the connecting rod 153, and the electric push rod 17 on the right side of the connecting rod 153 can control the height of the material limiting frame 15 to facilitate material discharging.

As shown in fig. 1 and 2, as shown in the figure, the right side of the sliding cover 3 is rotatably connected with a second sliding cover 31, the second sliding cover 31 is rotatably connected with the sliding cover 3, so that when a user drives the driving gear 9, the second sliding cover 31 can only be rotated, and the sliding cover 3 is not affected, the second sliding cover 31 is provided with a fixture block fixing groove 22 for placing the sliding fixture block 23 therein, the right side of the second sliding cover 31 is provided with a turnover fixing frame 7 for installing the turnover fixing wheel 26 therein, the turnover fixing frame 7 can clamp a curved material, and then the second sliding cover 31 is rotated to turn the material, when the user specifically operates, the user needs to firstly move the turnover fixing frame 7 with the turnover fixing wheel 26 to the rear of the curved position of the material, so that the curved position of the material is located in the area between the fixing cover 2 and the turnover fixing wheel 26, then, a user can enable the driving gear 9 to be meshed with the driving rack 91 by starting the driving motor, so that the second sliding cover 31 can be rotated, then the materials can be turned over by the turning fixed wheel 26, the spring 121 is installed on the side wall of the turning fixed wheel 26, the spring 121 connected to the turning fixed wheel 26 can enable the materials with different thicknesses to be clamped tightly, the pressing frame 24 internally provided with the anti-rebound pressing block 25 is arranged on one side of the sliding clamping block 23 close to the turning fixed wheel 26, the pressing frame 24 can drive the anti-rebound pressing block 25 to enable the anti-rebound pressing block to perform pressing operation on the turned materials, so that the situation of rebound and tilting of the materials is avoided, during specific operation, the user can directly open the driving motor on the cylindrical cam 19 to enable the cylindrical cam 19 to rotate, and then the straight rod on the cylindrical cam 19 can slide along the cylindrical cam 19, therefore, the front and back movement is realized, the straight rod which moves back and forth can pull the rotary connecting frame 21, so that the anti-rebound pressing block 25 and the flattening frame 24 slide along the material together, the material is pre-flattened, and the situation that the material rebounds and tilts does not occur;

as shown in fig. 1, 2 and 4, a spring 121 is installed on a side wall of the anti-rebound pressing block 25, the spring 121 connected to the anti-rebound pressing block 25 can enable materials of different thicknesses to be clamped and flattened, and has adjustability, so that the application range of the device is wide, the sliding fixture block 23 is provided with a rotating connection frame 21 provided with a sliding fixture sleeve 211 on a side wall far away from the overturn fixing wheel 26, a ball is arranged in the sliding fixture sleeve 211, when the second sliding cover 31 rotates, the straight rod can slide along the sliding fixture sleeve 211, so that the normal use of the device is not affected, the right side of the sliding cover 3 is welded and fixed with a clamping cover 8, a driving motor connected with a driving gear 9 on the right side is installed on a side wall above the clamping cover 8, the driving gear 9 can control the rotation of the second sliding cover 31 and the sliding cover 3, so that the overturn fixing frame 7 can rotate, thereby the upset of material to the adjustment position, and the fixed cover 20 of cam that the left side is connected driving motor is installed to the below inner wall of screens cover 8, be provided with in the fixed cover 20 of cam and fix the cylindrical cam 19 that covers 20 and rotate and be connected, the straight-bar with slip cutting ferrule 211 sliding connection is installed to the lateral wall of cylindrical cam 19.

As shown in fig. 1, a rack 91 engaged with the driving gear 9 is disposed on a side wall of the second sliding cover 31, the rack 91 is engaged with the driving gear 9, and a user can rotate the second sliding cover 31 by rotating the driving gear 9, and then the material can be turned over.

As shown in fig. 1, the rack plate 5 is arranged on the left side area of the sliding cover 3 at the clamping cover 8, the rack plate 5 can control the position of the turnover fixing frame 7, so that the rack plate can move to the rear of the bending position of the material, so that the bent material can be normally turned and adjusted, the fixing fixture block groove 132 of the material limiting fixing fixture block 131 is arranged in the first roller 13, the tension spring 133 is arranged on the side wall of the material limiting fixing fixture block 131, the tension spring 133 can tension the two material limiting fixing fixture blocks 131, and when the material is sent out, the tension spring 133 can tension the material limiting fixing fixture block 131 to realize secondary limitation, so that the material pressure delay cannot be easily influenced.

As shown in fig. 1, gear fixing through holes 61 of the internally mounted rotating gear 6 are formed in the outer wall of the upper portion of the limiting cover 4, a driving motor which is rotatably connected with the rotating gear 6 through a belt pulley is arranged above the rotating gear 6, so that the overturning fixing frame 7 can be moved to a proper position, and the overturning adjustment of the material cannot be influenced.

It is obvious to a person skilled in the art that the invention is not restricted to details of the above-described exemplary embodiments, but that it can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein. Any reference sign in a claim should not be construed as limiting the claim concerned.

Claims

1. The utility model provides an aluminium is rolled up turning device of processing with calender which characterized in that: including main part (1), main part (1) is including fixed cover (2) and the slip cover (3) that fixed cover (2) overcoat was established, slip cover (3) overcoat is equipped with spacing cover (4) with fixed cover (2) welded fastening, and slides cover (3) and fixed cover (2) sliding connection, lead screw fixed slot (10) of internally mounted drive lead screw (11) are seted up to the top inner wall of fixed cover (2), the left side of drive lead screw (11) is connected with driving motor, and drives lead screw (11) overcoat and be equipped with sliding sleeve (12) of internally mounted spring (121), pre-compaction gimbal (122) are installed to the below of spring (121), material spacing frame (15) are installed to the below of pre-compaction gimbal (122), and install first gyro wheel (13) and second gyro wheel (14) in the left side of pre-compaction gimbal (122), the second about fixed cover (2) center axis symmetry is installed about two on the right side of pre-compaction gimbal (122), two A roller (14);

the pre-pressing flat frame (122) comprises a fixed support frame (1221) and a plurality of connecting columns (1224) which are connected with the fixed support frame (1221) through screws, a plurality of heating blocks (1223) with heating resistance wires arranged inside are sleeved outside the connecting columns (1224), and auxiliary pressing flat sleeves (1222) which are connected with the heating blocks (1223) in a sliding mode are sleeved outside the heating blocks (1223);

the material limiting frame (15) comprises a first pressing plate (151) with a pressing sleeve through hole formed in the upper surface and a second pressing plate (152) connected with the first pressing plate (151) in a clamping mode, sliding limiting clamping grooves (154) with limiting clamping blocks (155) placed inside are formed in the inner wall of the upper portion of the second pressing plate (152), supporting covers (18) which are symmetrical to the central axis of the second pressing plate (152) are arranged on the left side and the right side of the lower surface of the second pressing plate (152), the number of the supporting covers (18) is two, springs (121) are installed in the two supporting covers (18), a connecting rod (153) with an electric push rod (17) installed below is rotatably connected to the bottom of each limiting clamping block (155), connecting rod supporting blocks (16) which are rotatably connected with the connecting rod (153) through rotating shafts are arranged on the left side and the right side of the connecting rod (153), and the connecting rod (153) is connected with the electric push rod (17), an electric push rod (17) connected with the second pressing plate (152) through a screw is arranged on the right side of the connecting rod (153).

2. The turning device of the calender for processing the aluminum coil according to claim 1, wherein: the right side of the sliding cover (3) is rotatably connected with a second sliding cover (31), a fixture block fixing groove (22) for placing a sliding fixture block (23) inside is formed in the second sliding cover (31), an overturning fixing frame (7) for installing an overturning fixing wheel (26) inside is arranged on the right side of the second sliding cover (31), a spring (121) is installed on the side wall of the overturning fixing wheel (26), a pressing frame (24) for installing a rebound-preventing pressure block (25) inside is arranged on one side, close to the overturning fixing wheel (26), of the sliding fixture block (23), a spring (121) is installed on the side wall of the rebound-preventing pressure block (25), a rotating connecting frame (21) for installing a sliding fixture sleeve (211) on the side wall is arranged on one side, far away from the overturning fixing wheel (26), and a clamping cover (8) is fixedly welded on the right side of the sliding cover (3), the driving motor that drive gear (9) was connected on the right side is installed to the top lateral wall of screens cover (8), and the below inner wall of screens cover (8) installs the fixed cover of cam (20) that the driving motor was connected on the left side, be provided with in the fixed cover of cam (20) and rotate cylindrical cam (19) of being connected with the fixed cover of cam (20), the straight-bar with slip cutting ferrule (211) sliding connection is installed to the lateral wall of cylindrical cam (19).

3. The turning device of the calender for processing the aluminum coil according to claim 2, characterized in that: and a rack (91) meshed with the driving gear (9) is arranged on the side wall of the second sliding cover (31).

4. The turning device of a calender for processing an aluminum coil according to claim 1 or 2, characterized in that: the rack plate (5) is arranged on the left side area of the side wall of the sliding cover (3) on the clamping cover (8), a fixed clamping block groove (132) of an internally-mounted material limiting fixed clamping block (131) is formed in the first roller (13), and a tension spring (133) is arranged on the side wall of the material limiting fixed clamping block (131).

5. The turning device of the calender for processing the aluminum coil according to claim 1, wherein: the gear fixing through hole (61) of internally mounted rotating gear (6) is formed in the outer wall of the upper portion of the limiting cover (4), and a driving motor which is rotatably connected with the rotating gear (6) through a belt pulley is arranged above the rotating gear (6).