CN111136528A

CN111136528A - Automatic feeding device of compressor blade clamp

Info

Publication number: CN111136528A
Application number: CN202010028149.6A
Authority: CN
Inventors: 殷建群; 李衬吉; 高卫国; 王磊; 刘海彬
Original assignee: Shijiazhuang Huaping Bearing Equipment Co Ltd
Current assignee: Shijiazhuang Huaping Bearing Equipment Co Ltd
Priority date: 2020-01-10
Filing date: 2020-01-10
Publication date: 2020-05-12

Abstract

The invention relates to an automatic feeding device of a compressor blade clamp, which comprises a base arranged on one side of the clamp, a supporting plate arranged on the base, a material box arranged on the supporting plate, a top plate arranged below the material box, a push plate arranged on one side of a positioning block, a pushing mechanism arranged on the supporting plate and driving the push plate to move, and a lifting mechanism arranged on the base and driving the top plate to move; the inside cavity and the top of material case are equipped with the opening with blade looks adaptation, the area of roof is less than the area of blade, the logical groove of roof looks adaptation is seted up to material bottom of the case end. It can realize the automatic feeding to blade anchor clamps, and is accurate with the rotation time cooperation of anchor clamps, improves the availability factor of anchor clamps.

Description

Automatic feeding device of compressor blade clamp

Technical Field

The invention relates to the technical field of tool fixtures for double-ended grinding machines, in particular to an automatic feeding device for a compressor blade fixture.

Background

A rotary vane compressor, also called a sliding vane machine or a rotary vane, is a compressor that converts mechanical energy into wind energy by rotating a vane to compress gas. As shown in fig. 1, two trapezoidal grooves 11 are formed in one end of each blade 1, the two grooves 11 are symmetrically arranged, one end of each blade 1, which is far away from the two grooves 11, is an arc surface 12, the axis of the arc surface 12 is perpendicular to two axial end surfaces 13 of the blade 1 along the arc surface 12, and the distance between each two grooves 11 and the two end surfaces 13 is the same. When the compressor works, the two end surfaces 13 of the blade 1 are simultaneously contacted with an upper cylinder cover and a lower cylinder cover of the compressor, and the sealing degree of the blade, the upper cylinder cover and the lower cylinder cover is ensured by the perpendicularity of the two end surfaces 13 of the blade 1 and the axis of the cambered surface 12.

When the blade is machined, a double-ended grinding machine is usually adopted to grind the upper end surface of the blade so as to ensure the machining precision of the blade. At present, the patent document of publication number for rotating sleeve N202317987U discloses a compressor blade double-ended grinder anchor clamps, include the base and fix the base on the base, the base on have a constant head tank, its characterized in that, the bottom surface of constant head tank on be fixed with the bottom bolster that supplies the blade bottom surface to support and lean on, be fixed with the side bolster that supplies the blade side to support on a side of constant head tank, another lateral part of constant head tank be equipped with the pressure head, pressure head and base between be equipped with and enable the pressure head and can be close to or the drive clamping mechanism who keeps away from to the side bolster.

Although the clamp for the compressor blade double-ended grinding machine can clamp and fix the blade, the blade still needs to be manually placed between the side cushion block and the pressure head, the work efficiency is low, the rotating interval time of the clamp cannot be accurately mastered, and the work efficiency of the clamp is reduced.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide the automatic feeding device of the compressor blade clamp, which can realize the automatic feeding of the blade clamp, is accurately matched with the rotation time of the clamp and improves the use efficiency of the clamp.

The above object of the present invention is achieved by the following technical solutions:

an automatic feeding device of a compressor blade clamp comprises a base arranged on one side of the clamp, a supporting plate arranged on the base, a material box arranged on the supporting plate, a top plate arranged below the material box, a push plate arranged on one side of a positioning block, a pushing mechanism arranged on the supporting plate and driving the push plate to move, and a lifting mechanism arranged on the base and driving the top plate to move;

the inside cavity and the top of material case are equipped with the opening with blade looks adaptation, the area of roof is less than the area of blade, the logical groove of roof looks adaptation is seted up to material bottom of the case end.

Through adopting above-mentioned technical scheme, place a plurality of blades in the material case to make a plurality of blades arrange the distribution along the direction of height in the material incasement, and two adjacent blades of material incasement contradict each other, because the logical groove area of material bottom of the case portion is less than the blade area, so the blade of below can not fall out the material case from leading to the groove. Elevating system drives the roof upward movement, and the roof gets into the material incasement from leading to the groove to drive a plurality of blades of material incasement upward movement simultaneously, align with the push pedal after being located the blade of the top by ejecting material case, push mechanism drives the push pedal and moves to anchor clamps one side afterwards, thereby with blade propelling movement to anchor clamps in. Then push mechanism drives the push pedal and resumes initial position, and the roof continues upward movement and releases next blade to accomplish the automatic feeding function to anchor clamps, and accurate with the action time cooperation of anchor clamps, improved the availability factor of anchor clamps.

The present invention in a preferred example may be further configured to: the material case's top is provided with the locating piece, the inside cavity and the bottom of locating piece are equipped with the opening, the side that the locating piece is close to anchor clamps is seted up with the discharge gate of blade looks adaptation, the push pedal runs through the locating piece and is connected rather than sliding.

By adopting the technical scheme, the positioning block has a positioning function on the blade of the ejection material box, so that the ejection material box cannot generate position deviation due to external action to influence the position relation between the push plate and the blade.

The present invention in a preferred example may be further configured to: the supporting plate is provided with a groove matched with the material box, and the top end of the material box is positioned in the groove and fixedly connected with the supporting plate.

By adopting the technical scheme, the material box has a positioning function when being installed, the material box is convenient to install, and the occupied space of the whole structure is reduced.

The present invention in a preferred example may be further configured to: the pushing mechanism comprises a mounting plate which is fixedly arranged on the base and positioned above the supporting plate, an air cylinder arranged on the mounting plate, and a connecting block fixedly arranged between a piston rod of the air cylinder and the pushing block; the mounting plate is fixedly connected with the push block.

Through adopting above-mentioned technical scheme, the motion that uses the cylinder piston rod drives the push pedal and removes, is convenient for adjust the motion stroke of push pedal to make overall structure simple and compact, guaranteed the stability of push mechanism function.

The present invention in a preferred example may be further configured to: the base is fixedly provided with a central shaft, the supporting plate sleeve is arranged on the central shaft and is connected with the central shaft in a rotating mode, the supporting plate is provided with a plurality of material boxes which are distributed along the circumferential interval of the central shaft, the base is provided with a driving mechanism for driving the supporting plate to rotate, and the mounting plate is fixedly connected with the central shaft.

Through adopting above-mentioned technical scheme, set up a plurality of material casees in with the backup pad, after the material incasement blade of roof top is by whole ejecting, the roof resumes initial position, actuating mechanism drives the backup pad and rotates afterwards, rotate another material case that contains the blade to the top of roof, and push mechanism can not garrulous rotation of backup pad and function, make loading attachment can continue to supply the blade in to anchor clamps, the staff of still being convenient for in time supplements the blade to the air material incasement, loading attachment's practicality has been improved.

The present invention in a preferred example may be further configured to: the supporting plate top surface sets firmly annular guide rail, the mounting panel bottom surface sets firmly the guide block, the guide block slides with annular guide rail and is connected.

Through adopting above-mentioned technical scheme, when the backup pad rotated, the guide block can slide on ring rail, does not interfere the rotation of backup pad promptly, has increased the strong point to the mounting panel again to stability when having improved the cylinder function has reduced the mounting panel and has appeared crooked phenomenon because of the weight of locating piece.

The present invention in a preferred example may be further configured to: the driving mechanism comprises a rotating sleeve, a worm wheel, a worm, a driving motor and a linkage assembly, wherein the rotating sleeve is sleeved on the fixed shaft and is in rotating connection with the fixed shaft; the supporting plate is fixedly connected with the rotating sleeve.

Through adopting above-mentioned technical scheme, driving motor passes through the linkage subassembly and drives the worm and rotate, and the worm wheel can rotate thereupon when the worm rotates to drive the backup pad through rotating the sleeve and rotate, the cooperation of worm wheel and worm plays the speed reduction function to driving motor's motion, and is more steady when making the backup pad rotate, and the cooperation of worm wheel and worm has auto-lock nature, makes the backup pad can not rotate because of external factors, has guaranteed the positioning accuracy of material case.

The present invention in a preferred example may be further configured to: the linkage assembly comprises a driving synchronous belt wheel fixedly arranged on an output shaft of the driving motor, a driven synchronous belt wheel fixedly arranged on the worm, and a toothed belt sleeved on the peripheral surfaces of the driving synchronous belt wheel and the driven synchronous belt wheel;

the toothed belt is meshed with the driving synchronous belt wheel and the driven synchronous belt wheel respectively.

Through adopting above-mentioned technical scheme, when driving motor's output shaft rotated, drive synchronous pulley can rotate along with it to drive driven synchronous pulley through the cog belt and rotate, and then make driving motor drive the worm and rotate, make the drive ratio between driving motor and the worm accurate, compact structure, and under linkage assembly's effect, driving motor sets up in the below of base, makes loading attachment's whole focus move down, make loading attachment be difficult to appear rocking when using.

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

1. the blades are placed in the material box, the top plate is used for ejecting the blades in the material box one by one, the ejecting blades are pushed to the clamp by the pushing plate, automatic feeding of the blades can be achieved through reciprocating motion, the blades are accurately matched with the action distance of the clamp, and the use efficiency of the clamp is improved;

2. the material boxes are arranged on the supporting plate, the supporting plate can rotate, after all blades in one material box are ejected, the material boxes can be replaced in time by rotating the supporting plate, so that the feeding mechanism can continuously provide the blades for the clamp, workers can conveniently and timely supplement the blades to the empty material boxes, and the practicability of the feeding device is improved;

3. the top plate with the area smaller than that of the blade is adopted to drive the blade to move upwards, so that the area of the through groove at the bottom end of the material box is smaller than that of the blade, the blade cannot fall out of the through groove in the material box, the movement of the top plate is not interfered, the whole structure is compact, and the movement is stable.

Drawings

FIG. 1 is a schematic view of a blade configuration for a compressor;

FIG. 2 is a schematic structural diagram of the positional relationship between the loading device and the clamp;

fig. 3 is a sectional view showing an internal structure of the material tank and the pushing mechanism;

FIG. 4 is a sectional view showing a blade contained in the material tank;

fig. 5 is a sectional view showing the drive mechanism.

In the figure, 1, a blade; 11. a groove; 12. a cambered surface; 13. an end face; 2. a clamp; 3. a base; 31. a central shaft; 32. a support plate; 4. a material box; 41. a through groove; 5. a top plate; 6. a lifting mechanism; 61. a lifting screw; 62. a slider; 63. a connecting plate; 62. a yielding groove; 64. a guide bar; 65. a lifting motor; 7. positioning blocks; 71. a discharge port; 72. pushing the plate; 8. a pushing mechanism; 81. mounting a plate; 82. a cylinder; 83. connecting blocks; 84. an annular guide rail; 85. a guide block; 9. a drive mechanism; 91. rotating the sleeve; 92. a worm gear; 93. a worm; 94. a drive motor; 95. a linkage assembly; 951. driving a synchronous pulley; 952. a driven synchronous pulley; 953. a toothed belt.

Detailed Description

The present invention will be described in further detail with reference to the accompanying drawings.

Referring to fig. 2, the automatic feeding device for the compressor blade fixture disclosed by the invention is arranged on one side of a feeding port of the fixture 2. Automatic feeding device includes base 3, and the top of base 3 is provided with center pin 31, and center pin 31 sets up along the direction of height, and the bottom and the base 3 fixed connection of center pin 31. A supporting plate 32 is arranged above the base 3, the supporting plate 32 is arranged in a circular plate shape, the axis of the supporting plate 32 is overlapped with the axis of the central shaft 31, and the supporting plate 32 is sleeved on the central shaft 31 and is rotatably connected with the central shaft 31.

Referring to fig. 3 and 4, the support plate 32 is provided with a plurality of material tanks 4, and the plurality of material tanks 4 are uniformly distributed along the axial direction of the support plate 32. Material case 4 is the cuboid that vertical direction set up, and the inside cavity and the top of material case 4 are equipped with the opening, and material case 4 is inside to be used for holding a plurality of blades 1, and a plurality of blades 1 are located and arrange along the direction of height in material case 4, and two adjacent blades 1 in the material case 4 are contradicted mutually, and the top opening of material case 4 is in 1 looks adaptation of blade. The supporting plate 32 is provided with a groove 11 matched with the material tank 4, the top end of the material tank 4 is positioned in the groove 11 and fixedly connected with the supporting plate 32, and the top end of the material tank 4 and the top end of the supporting plate 32 are positioned on the same plane.

Referring to fig. 3, a top plate 5 is arranged below the material tank 4 close to the clamp 2, the top plate 5 is arranged along the horizontal direction, the area of the top plate 5 is smaller than that of the blade 1, a through groove 41 matched with the top plate 5 is formed in the bottom wall of the material tank 4, namely, the area of the through groove 41 is smaller than that of the blade 1, and therefore the blade 1 cannot fall out of the material tank 4 from the through groove 41. Be provided with elevating system 6 on base 3, elevating system 6 can drive roof 5 along the direction of height motion, and when elevating system 6 drove roof 5 upward movement, roof 5 through lead to groove 41 get into material case 4 in the back, continue upward movement and can be ejecting from the top opening part of material case 4 with blade 1 in the material case 4.

Referring to fig. 3, a positioning block 7 is arranged above the material box 4 close to one side of the clamp 2, the positioning block 7 is connected to the supporting plate 32 in an abutting mode, the positioning block 7 is hollow inside, an opening is formed in the bottom end of the positioning block 7, and the size of the opening in the bottom end of the positioning block 7 is matched with that of the blade 1. The discharge hole 71 is formed in the side wall of one end, close to the clamp 2, of the positioning block 7, the top wall of the discharge hole 71 is located on the same horizontal plane, a push plate 72 is arranged on one side, far away from the discharge hole 71, of the positioning block 7, the push plate 72 is arranged in the horizontal direction and located above the supporting plate 32, the thickness of the push plate 72 is smaller than that of the blade 1, and one end of the push plate 72 penetrates through the positioning block 7 to be connected with the positioning block in a sliding mode. A pushing mechanism 8 is arranged above the supporting plate 32, and the pushing mechanism 8 is used for driving the pushing plate 72 to move along the horizontal direction.

Referring to fig. 4, the uppermost blade 1 in the material tank 4 is ejected out of the material tank 4 by the top plate 5 and then enters the baffle plate, and abuts against the top wall of the baffle plate, at this time, the blade 1 corresponds to the discharge hole 71, and then the pushing mechanism 8 drives the pushing plate 72 to move towards one side of the fixture 2, so that the blade 1 is pushed out from the discharge hole 71 and enters the fixture 2, and thus, the automatic feeding function of the blade 1 can be realized by repeated operation.

Referring to fig. 4, a driving mechanism 9 is further arranged on the base 3, the driving mechanism 9 is used for driving the supporting plate 32 to rotate along the axis of the central shaft 31, after the blades 1 in the material box 4 close to one side of the clamp 2 are all ejected out, the top plate 5 moves downwards to the lower side of the material box 4, then the driving mechanism 9 drives the supporting plate 32 to rotate, so that the other material box 4 containing the blades 1 rotates to the upper side of the top plate 5, the blades 1 can be continuously supplied to the clamp 2, the empty material box 4 can be rotated out from the lower side of the positioning block 7, and a worker can place the blades 1 which are processed instead into the empty material box 4, so that the automatic feeding device can continuously feed the clamp 2.

Referring to fig. 3, the lifting mechanism 6 includes a lifting screw 61, the lifting screw 61 is located between the base 3 and the top plate 5, the lifting screw 61 is disposed along the vertical direction, the lifting screw 61 is rotatably connected with the base 3 along two axial ends of the lifting screw 61, and the lifting screw 61 is spaced from the material box 4. Threaded connection has slider 62 on the lifting screw 61, has set firmly connecting plate 63 between slider 62 and the roof 5, and connecting plate 63 sets up along vertical direction. The side surface of the material box 4 close to the central shaft 31 is provided with a yielding groove 62 matched with the connecting plate 63, the yielding groove 62 is arranged along the height direction, and the width of the yielding groove 62 is smaller than that of the blade 1. The two sides of the lifting screw 61 are respectively provided with a guide rod 64, the guide rods 64 are arranged along the vertical direction, the guide rods 64 are respectively fixedly connected with the base 3 along the two axial ends of the guide rods 64, and the guide rods 64 penetrate through the sliding block 62 and are connected with the sliding block. Be provided with elevator motor 65 on the base 3, elevator motor 65's output shaft and lifting screw 61 fixed connection, and elevator motor 65 sets up to servo motor.

The lifting motor 65 drives the lifting screw 61 to rotate, so that the sliding block 62 is controlled to move along the axial direction of the lifting screw 61, the sliding block 62 drives the top plate 5 to move along the axial direction of the lifting screw 61 through the connecting plate 63, namely, the top plate 5 is driven to move along the height direction, the material box 4 is not interfered by the abdicating groove 62, the width of the abdicating groove 62 is smaller than that of the blade 1, and the blade 1 cannot fall out of the material box 4 from the abdicating groove 62.

Referring to fig. 3, the pushing mechanism 8 includes a mounting plate 81 disposed above the supporting plate 32, the mounting plate 81 is disposed along a horizontal direction, one end of the mounting plate 81 is fixedly connected to the top end of the central shaft 31, and one end of the mounting plate 81 far away from the central shaft 31 is fixedly connected to the top surface of the positioning block 7, i.e., the pushing plate 72 is located below the mounting plate 81. The top surface of mounting panel 81 is provided with cylinder 82, and the piston rod of cylinder 82 points to push pedal 72 one side, and has set firmly connecting block 83 between the piston rod of cylinder 82 and the one end of push pedal 72 far away from locating piece 7, and connecting block 83 runs through mounting panel 81 and is connected rather than sliding. The push plate 72 can be driven to move along the horizontal direction by extending or retracting the piston rod of the air cylinder 82, so that the function of pushing the blade 1 out of the discharge hole 71 by the push plate 72 is realized.

Referring to fig. 3, a ring-shaped guide rail 84 is fixedly arranged on the top surface of the support plate 32, the ring-shaped guide rail 84 is arranged in a ring shape, the axis of the ring-shaped guide rail 84 is overlapped with the axis of the central shaft 31, and the push plate 72 is located on the side of the ring-shaped guide rail 84 away from the central shaft 31. The bottom surface of the mounting plate 81 is fixedly provided with a guide block 85, and the guide block 85 is connected to the annular guide rail 84 in a sliding manner. When the support plate 32 rotates, since the mounting plate 81 is fixed to the central shaft 31, the mounting plate 81 does not rotate along with the support plate 32, and the guide block 85 and the ring rail 84 provide a supporting force to the mounting plate 81 so that the mounting plate 81 does not bend downward due to the weight of the positioning block 7.

Referring to fig. 5, the driving mechanism 9 includes a rotating sleeve 91 sleeved on the central shaft 31, an axis of the rotating sleeve 91 coincides with an axis of the central shaft 31, the rotating sleeve 91 is rotatably connected to the central shaft 31, a top end of the rotating sleeve 91 is fixedly connected to the supporting plate 32, and a bottom end of the rotating sleeve 91 is rotatably connected to the base 3. A worm gear 92 is fixedly arranged on the outer peripheral surface of the rotating sleeve 91, the worm gear 92 is positioned between the support plate 32 and the base 3, a worm 93 is arranged on one side of the worm gear 92 away from the lifting screw 61, the worm 93 is arranged along the horizontal direction, and two axial ends of the worm 93 are respectively connected with the base 3 in a rotating manner.

Referring to fig. 5, a driving motor 94 is disposed on the base 3, the driving motor 94 is a servo motor, and a linkage assembly 95 is disposed between an output shaft of the driving motor 94 and the worm 93. Linkage assembly 95 includes drive synchronous pulley 951, drive synchronous pulley 951 sets firmly on drive motor 94's output shaft, worm 93 has set firmly driven synchronous pulley 952 along its axial one end, drive synchronous pulley 951 is located same one side with driven synchronous pulley 952, and the cover is equipped with toothed belt 953 on drive synchronous pulley 951 and the driven synchronous pulley 952 outer peripheral face, toothed belt 953 meshes with drive synchronous pulley 951 and driven synchronous pulley 952 respectively, drive synchronous pulley 951 passes through the transmission of toothed belt 953 with driven synchronous pulley 952.

The driving motor 94 drives the driving synchronous belt pulley 951 to rotate, the driving synchronous belt pulley 951 drives the driven synchronous belt pulley 952 to rotate through the toothed belt 953, so that the worm 93 is driven to rotate, the worm gear 92 is driven to rotate when the worm 93 rotates, the rotating sleeve 91 and the supporting plate 32 are driven to rotate, and the replacing function of the material box 4 is realized. And the driving synchronous belt wheel 951, the driven synchronous belt wheel 952 and the toothed belt 953 ensure the transmission precision of the driving motor 94, the worm 93 and the worm gear 92 are matched to play a role in speed reduction, so that the support plate 32 is stable in rotation, and has self-locking property, so that the support plate 32 cannot be rotated by external force, and the use stability of the automatic feeding device is ensured.

The embodiments of the present invention are preferred embodiments of the present invention, and the scope of the present invention is not limited by these embodiments, so: all equivalent changes made according to the structure, shape and principle of the invention are covered by the protection scope of the invention.

Claims

1. The utility model provides a compressor blade anchor clamps's automatic feeding device which characterized in that: the device comprises a base (3) arranged on one side of a clamp (2), a supporting plate (32) arranged on the base (3), a material box (4) arranged on the supporting plate (32), a top plate (5) arranged below the material box (4), a push plate (72) arranged on one side of a positioning block (7), a pushing mechanism (8) arranged on the supporting plate (32) and used for driving the push plate (72) to move, and a lifting mechanism (6) arranged on the base (3) and used for driving the top plate (5) to move;

the inside cavity and the top of material case (4) are equipped with the opening with blade (1) looks adaptation, the area of roof (5) is less than the area of blade (1), logical groove (41) with roof (5) looks adaptation are seted up to material case (4) bottom.

2. The automatic feeding device of a compressor blade fixture of claim 1, wherein: the material box is characterized in that a positioning block (7) is arranged above the material box (4), an opening is formed in the hollow interior and the bottom end of the positioning block (7), a discharge hole (71) matched with the blade (1) is formed in the side face, close to the clamp (2), of the positioning block (7), and the push plate (72) penetrates through the positioning block (7) and is connected with the positioning block in a sliding mode.

3. The automatic feeding device of a compressor blade fixture of claim 1, wherein: the supporting plate (32) is provided with a groove (11) matched with the material box (4), and the top end of the material box (4) is positioned in the groove (11) and fixedly connected with the supporting plate (32).

4. The automatic feeding device of a compressor blade fixture of claim 1, wherein: the pushing mechanism comprises a mounting plate (81) which is fixedly arranged on the base (3) and is positioned above the supporting plate (32), an air cylinder (82) arranged on the mounting plate (81), and a connecting block (83) which is fixedly arranged between a piston rod of the air cylinder (82) and the pushing block; the mounting plate (81) is fixedly connected with the push block.

5. The automatic feeding device of compressor blade fixture according to any one of claims 1 to 4, wherein: the utility model discloses a material storage device, including base (3), backup pad (32), a plurality of material casees (4), a plurality of material case (4) are provided with circumference interval distribution along center pin (31) on base (3), center pin (31) are established to backup pad (32) cover, it is connected rather than rotating on center pin (31), be provided with on backup pad (32) and drive backup pad (32) pivoted actuating mechanism (9), mounting panel (81) and center pin (31) fixed connection.

6. The automatic feeding device of a compressor blade fixture of claim 5, wherein: the supporting plate (32) top surface sets firmly ring rail (84), mounting panel (81) bottom surface sets firmly guide block (85), guide block (85) and ring rail (84) slide and are connected.

7. The automatic feeding device of a compressor blade fixture of claim 5, wherein: the driving mechanism (9) comprises a rotating sleeve (91) sleeved on the fixed shaft and rotationally connected with the fixed shaft, a worm wheel (92) fixedly arranged on the rotating sleeve (91), a worm (93) rotationally connected to the base (3) and meshed with the worm wheel (92), a driving motor (94) arranged on the base (3), and a linkage assembly (95) arranged between the driving motor (94) and the worm (93); the supporting plate (32) is fixedly connected with the rotating sleeve (91).

8. The automatic loading device of a compressor blade fixture of claim 7, wherein: the linkage assembly (95) comprises a driving synchronous pulley (951) fixedly arranged on an output shaft of the driving motor (94), a driven synchronous pulley (952) fixedly arranged on the worm (93), and a toothed belt (953) sleeved on the outer peripheral surfaces of the driving synchronous pulley (951) and the driven synchronous pulley (952);

the toothed belt (953) is meshed with the driving synchronous belt wheel (951) and the driven synchronous belt wheel (952) respectively.