CN111283452B

CN111283452B - Clamping and positioning fixture for arc surface workpiece

Info

Publication number: CN111283452B
Application number: CN202010335283.0A
Authority: CN
Inventors: 尹雪
Original assignee: Jiangsu Airship Gear Corp
Current assignee: Jiangsu Airship Gear Corp
Priority date: 2020-04-24
Filing date: 2020-04-24
Publication date: 2020-11-24
Anticipated expiration: 2040-04-24
Also published as: CN111283452A; GB202010463D0

Abstract

The invention discloses a clamping and positioning clamp for an arc surface workpiece, which comprises a rotating disc and a base, wherein the rotating disc is abutted against the upper end of the base, three clamping devices are arranged on the upper side of the rotating disc, the clamping devices on the left side and the right side are positioned on the same horizontal plane, the clamping devices on the rear side are higher than the clamping devices on the left side and the right side, the clamping devices comprise fixed grippers and movable grippers, and the movable grippers are positioned on one side of the fixed grippers in the clockwise direction. Thereby ensuring the positioning effect.

Description

Clamping and positioning fixture for arc surface workpiece

Technical Field

The invention relates to the field of clamps, in particular to a clamping and positioning clamp for a workpiece with an arc surface.

Background

The machine tool clamp is one of important technical equipment which ensures the machining quality, improves the production efficiency, lightens the labor intensity, reduces the overhigh requirement on the technology of workers and realizes the automation of the production process, the machine tool clamp is widely used in the manufacturing industry, the use of a large number of special machine tool clamps provides necessary conditions for mass production, but in the existing machining process, generally cylindrical or square machined parts are used for machining, and truncated cone-shaped and conical machined parts are rare, so when the truncated cone-shaped or conical workpiece is machined, corresponding clamps are required to be arranged, the machining cost is further improved, the sizes of the workpieces are different, the sizes of the clamps are also different, and the inconvenience is brought to the machining of the truncated cone-shaped or conical workpiece, and the clamping and positioning clamp for the arc surface workpiece is explained in the invention, the above problems can be solved.

Disclosure of Invention

In order to solve the problems, the embodiment designs a clamping and positioning clamp for an arc-surface workpiece, the clamping and positioning clamp for the arc-surface workpiece comprises a rotating disc and a base, the rotating disc is abutted against the upper end of the base, three clamping devices are arranged on the upper side of the rotating disc, the clamping devices on the left side and the right side are positioned on the same horizontal plane, the clamping devices on the rear side are higher than the clamping devices on the left side and the right side, each clamping device comprises a fixed gripper and a movable gripper, the movable gripper is positioned on one side of the fixed gripper in the clockwise direction, an adjusting screw rod is in threaded connection between the fixed gripper and the movable gripper, the fixed gripper and the movable gripper are abutted against the arc surface of the circular truncated cone workpiece and clamp the circular truncated cone workpiece, and the fixed gripper and the movable gripper on the left side and the right side are used for clamping the circular truncated cone workpiece, a spring groove with an opening facing the fixed gripper is arranged in the movable gripper, a guide rod is fixedly connected to one end, close to the movable gripper, of the fixed gripper, the guide rod extends into the spring groove and is in sliding connection with the movable gripper, a clamping spring is fixedly connected between the guide rod and the inner wall of the spring groove, the fixed gripper and the movable gripper on the rear side are used for reducing shaking of a round platform workpiece, the adjusting screw rod is manually rotated to adjust the distance between the fixed gripper and the movable gripper, so that the fixed gripper and the movable gripper can be attached to the arc surface of the round platform workpiece, when the fixed gripper and the movable gripper are in a propping state, the clamping spring is in a normal state, the adjusting screw rod is rotated to drive the movable gripper to slide, so that the clamping spring is stretched, and when the fixed gripper and the movable gripper are attached to the workpiece, the fixed grippers and the movable grippers clamp workpieces under the elastic force action of the clamping springs, a cavity is arranged in the rotating disc, a vertical sliding block is arranged in the cavity in a vertical sliding mode, the peripheral surface of the vertical sliding block is symmetrical about the vertical sliding block, three connecting rods are distributed in an annular array and hinged to the peripheral surface of the vertical sliding block, a push rod is hinged to the upper end of each connecting rod, a support rod is hinged to one end, away from the vertical sliding block, of each push rod, the upper ends of the three support rods are fixedly connected to the three fixed grippers respectively, when the vertical sliding block slides upwards, the connecting rods are driven to swing to one side, away from the vertical sliding block, the push rods are driven to move to one side, away from the vertical sliding block, the support rods are driven to move to one side, away from the vertical sliding, and then make fixed tongs with remove the tongs can adapt to the round platform work piece of different diameters, the rolling disc upper end is connected with positioner, positioner includes bilateral symmetry's pilot pin, the pilot pin sliding connection in the rolling disc, the rolling disc upper end has linked firmly the fixed block, the fixed block is located both sides between the pilot pin, be equipped with the opening in the pilot pin towards the chamber that holds of fixed block, be equipped with the transmission chamber in the fixed block, the transmission intracavity upside inner wall intercommunication be equipped with the ascending smooth chamber of leading of opening, it is equipped with the sleeve to slide from top to bottom in the smooth chamber of leading, the sleeve upper end stretches out the smooth chamber of leading, the sleeve left and right ends symmetry just articulates there is the locating clip, links firmly extension spring between the locating clip of both sides, when the pilot pin of both sides is close to each other and slides, fixed block, The positioning clamp is arranged in the containing cavity, the upper end of the positioning needle abuts against the plane end face of the circular truncated cone workpiece at the moment, the circular truncated cone workpiece is positioned, when the diameter of the plane end face of the circular truncated cone workpiece is zero, namely the workpiece is in a conical shape, the positioning needle on the two sides cannot position the circular truncated cone workpiece at the moment, the positioning needles on the two sides are far away from each other and slide, the sleeve slides upwards at the moment, the top point of the circular truncated cone workpiece extends into the space between the positioning clamps on the two sides and pushes the positioning clamps to swing, the positioning clamps on the two sides have the same swing angle, the positioning of the circular truncated cone workpiece is completed, and the extension spring is in a stretching state at the moment.

Preferably, the inner wall of the upper side of the cavity is provided with three guide grooves which are communicated with each other and distributed in an annular array by taking the vertical sliding block as a symmetric center, the openings of the guide grooves are upward, the three support rods respectively penetrate through the three guide grooves, the support rods slide along the guide grooves, the guide grooves guide the support rods, the inner wall of the lower side of the cavity is provided with three moving grooves which are communicated with each other and distributed in an annular array by taking the vertical sliding block as a symmetric center, the lower ends of the three support rods respectively extend into the three moving grooves, a buffer spring is fixedly connected between one end of each support rod, which is far away from the vertical sliding block, and the inner wall of the moving groove, which is far away from the vertical sliding block, the support rods slide and compress the buffer spring, and the support rods are buffered under the elastic force of the, it uses vertical slider to be symmetrical center and the dead lever that the annular array distributes, three to link firmly on the cavity inner wall the dead lever downside is equipped with the decurrent sliding tray of opening, be equipped with the connecting block in the sliding tray, the connecting block is in slide in the sliding tray, the connecting block with one side that the push rod is close to the center is articulated, the connecting block is right the push rod and the slip of bracing piece is led.

Preferably, the inner thread of the vertical sliding block is connected with a lifting screw rod, the lower end of the lifting screw rod is rotatably connected with the base, a motor is fixedly arranged in the base, the lower end of the lifting screw rod is in power connection with the motor, the motor is started, and the vertical sliding block is driven to slide up and down through the lifting screw rod.

Preferably, a driving bevel gear is rotatably arranged in the transmission cavity, a rotating shaft is fixedly connected to the front end of the driving bevel gear, a sliding bevel gear is arranged at the upper end of the driving bevel gear in a meshed manner, a moving shaft is fixedly connected to the upper end of the sliding bevel gear, the upper end of the moving shaft is in threaded connection with the sleeve, moving bevel gears are symmetrically and rotatably arranged at the left and right ends of the driving bevel gear, the moving bevel gears are meshed with the driving bevel gear, a sliding screw rod is fixedly connected to the mutually far ends of the moving bevel gears, moving cavities are symmetrically arranged in the inner walls at the left and right sides of the transmission cavity, the openings of the moving cavities are opposite, a ball screw nut is arranged in the moving cavity in a left-right sliding manner, the sliding screw rod extends into the moving cavity and is in threaded connection with the ball screw nut, the front end of the sliding block is fixedly connected with a moving rod, one end, far away from the transmission cavity, of the moving rod is fixedly connected with the positioning needle, a moving groove is formed in the inner wall of the rear side of the moving cavity in a communicated mode, the sliding block is arranged in the moving groove, the moving groove guides the sliding block in a sliding mode, the rotating shaft is rotated, the driving bevel gear is driven to rotate, the sliding bevel gear is driven to rotate, the sleeve is driven to slide up and down through the moving shaft, meanwhile, the driving bevel gear rotates and drives the moving bevel gear to rotate, the ball screw nut is driven to slide left and right through the sliding screw, the sliding block is driven to slide left and right through the sliding rod, and the positioning needle is driven to slide left and right through the moving rod.

The invention has the beneficial effects that: the movable gripper and the fixed gripper can be adjusted according to the diameter of the circular truncated cone or conical workpiece, so that the application range of clamping is further improved, the workpiece is guaranteed to be clamped and the shaking of the workpiece in the machining process is reduced through the position arrangement of the three pairs of grippers, the machining quality is further guaranteed, the positioning mode can be switched according to the type of the workpiece, and the positioning effect is further guaranteed.

Drawings

For ease of illustration, the invention is described in detail by the following specific examples and figures.

FIG. 1 is a schematic view of an overall structure of a clamping and positioning fixture for a circular arc workpiece according to the present invention;

FIG. 2 is a schematic view of the structure in the direction "A" of FIG. 1;

FIG. 3 is an enlarged schematic view of "B" of FIG. 1;

FIG. 4 is a schematic view of the structure in the direction "C" of FIG. 1;

FIG. 5 is an enlarged schematic view of "D" of FIG. 3;

FIG. 6 is a schematic structural view of a positioning pin;

FIG. 7 is a schematic view of the structure in the direction "E-E" of FIG. 2.

Detailed Description

The invention will now be described in detail with reference to fig. 1-7, for ease of description, the orientations described below will now be defined as follows: the up, down, left, right, and front-back directions described below correspond to the up, down, left, right, and front-back directions in the projection relationship of fig. 1 itself.

The invention relates to a clamping and positioning clamp for a circular arc workpiece, which comprises a rotating disc 16 and a base 24, wherein the rotating disc 16 is abutted against the upper end of the base 24, three clamping devices 102 are arranged on the upper side of the rotating disc 16, the clamping devices 102 on the left side and the right side are positioned on the same horizontal plane, the clamping device 102 on the rear side is higher than the clamping devices 102 on the left side and the right side, the clamping devices 102 comprise a fixed gripper 12 and a movable gripper 13, the movable gripper 13 is positioned on one side of the fixed gripper 12 in the clockwise direction, an adjusting screw rod 11 is in threaded connection between the fixed gripper 12 and the movable gripper 13, the fixed gripper 12 and the movable gripper 13 are abutted against the circular arc surface of the circular table workpiece and clamp the circular table workpiece, the fixed gripper 12 and the movable gripper 13 on the left side and the right side are used for clamping the circular table workpiece, and a spring groove 52 with an opening facing the fixed gripper 12 is arranged in the, one end of the fixed gripper 12 close to the movable gripper 13 is fixedly connected with a guide rod 51, the guide rod 51 extends into the spring groove 52 and is in sliding connection with the movable gripper 13, a clamping spring 53 is fixedly connected between the guide rod 51 and the inner wall of the spring groove 52, the fixed gripper 12 and the movable gripper 13 on the rear side are used for reducing the shaking of the circular truncated cone workpiece, the adjusting screw rod 11 is manually rotated to adjust the distance between the fixed gripper 12 and the movable gripper 13, so that the fixed gripper 12 and the movable gripper 13 can be attached to the circular arc surface of the circular truncated cone workpiece, when the fixed gripper 12 and the movable gripper 13 are in an abutting state, the clamping spring 53 is in a normal state, the adjusting screw rod 11 is rotated to drive the movable gripper 13 to slide, so as to stretch the clamping spring 53, and when the fixed gripper 12 and the movable gripper 13 are attached to the workpiece, under the elastic force of the clamping spring 53, the fixed gripper 12 and the movable gripper 13 clamp the workpiece, a cavity 15 is arranged in the rotating disc 16, a vertical slider 22 is arranged in the cavity 15 in a vertically sliding manner, the peripheral surface of the vertical slider 22 is symmetrical about the vertical slider 22, three connecting rods 21 are distributed in an annular array and hinged to the peripheral surface, a push rod 20 is hinged to the upper end of each connecting rod 21, one end of each push rod 20, far away from the vertical slider 22, is hinged to a support rod 14, the upper ends of the three support rods 14 are respectively and fixedly connected to the three fixed grippers 12, when the vertical slider 22 slides upwards, the connecting rods 21 are driven to swing towards the side far away from the vertical slider 22, the push rods 20 are driven to move towards the side far away from the vertical slider 22, the support rods 14 are driven to move towards the side far away from the vertical slider 22, and the fixed gripper 12 and the movable gripper 13 are driven to move, the fixed gripper 12 and the movable gripper 13 can be adapted to circular truncated cone workpieces with different diameters, the upper end of the rotating disc 16 is connected with a positioning device 101, the positioning device 101 comprises positioning pins 49 which are bilaterally symmetrical, the positioning pins 49 are slidably connected to the rotating disc 16, the upper end of the rotating disc 16 is fixedly connected with a fixed block 35, the fixed block 35 is positioned between the positioning pins 49 on two sides, an accommodating cavity 50 with an opening facing the fixed block 35 is arranged in the positioning pins 49, a transmission cavity 30 is arranged in the fixed block 35, a sliding guide cavity 38 with an upward opening is arranged in the inner wall on the upper side of the transmission cavity 30 in a communicating manner, a sleeve 27 is arranged in the sliding guide cavity 38 in a vertically sliding manner, the upper end of the sleeve 27 extends out of the sliding guide cavity 38, the left end and the right end of the sleeve 27 are symmetrically hinged with positioning clamps 26, and a tension spring 36 is fixedly connected, when the positioning pins 49 on the two sides approach to each other and slide, the fixing block 35, the sleeve 27 and the positioning clamp 26 are accommodated in the accommodating cavity 50, at this time, the upper ends of the positioning pins 49 abut against the planar end face of the circular truncated cone workpiece, and position the circular truncated cone workpiece, when the diameter of the planar end face of the circular truncated cone workpiece is zero, that is, the workpiece is conical, at this time, the positioning pins 49 on the two sides cannot complete the positioning of the circular truncated cone workpiece, at this time, the positioning pins 49 on the two sides are away from each other and slide, at this time, the sleeve 27 slides upwards, so that the vertex of the circular truncated cone workpiece extends into the space between the positioning clamps 26 on the two sides and pushes the positioning clamp 26 to swing, the positioning clamps 26 on the two sides swing at the same angle, the circular truncated cone workpiece is positioned, and at this time.

Beneficially, three guide grooves 48 which are symmetrical about the vertical sliding block 22 and are distributed in an annular array are arranged in the inner wall of the upper side of the cavity 15, the openings of the guide grooves 48 are upward, three support rods 14 respectively penetrate through the three guide grooves 48, the support rods 14 slide along the guide grooves 48, the guide grooves 48 guide the support rods 14, three moving grooves 18 which are symmetrical about the vertical sliding block 22 and are distributed in an annular array are arranged in the inner wall of the lower side of the cavity 15, the lower ends of the three support rods 14 respectively extend into the three moving grooves 18, a buffer spring 19 is fixedly connected between one end of each support rod 14, which is far away from the vertical sliding block 22, and the inner wall of the moving groove 18, which is far away from the vertical sliding block 22, the support rod 14 slides and compresses the buffer spring 19, and the sliding of the support rods 14 is buffered under the elastic force of the buffer spring 19, have linked firmly three dead lever 39 that use vertical slider 22 to distribute as center of symmetry and annular array on the cavity 15 inner wall, it is three dead lever 39 downside is equipped with the decurrent sliding tray 17 of opening, be equipped with connecting block 47 in the sliding tray 17, connecting block 47 is in slide in the sliding tray 17, connecting block 47 with push rod 20 is close to one side at center articulated, connecting block 47 is right push rod 20 and the slip of bracing piece 14 leads.

Beneficially, a lifting screw 23 is connected to the vertical slider 22 through an internal thread, the lower end of the lifting screw 23 is rotatably connected to the base 24, a motor 25 is fixedly arranged in the base 24, the lower end of the lifting screw 23 is connected to the motor 25 through power, the motor 25 is started, and the vertical slider 22 is driven to slide up and down through the lifting screw 23.

Beneficially, a driving bevel gear 37 is rotatably arranged in the transmission cavity 30, a rotating shaft 41 is fixedly connected to the front end of the driving bevel gear 37, a sliding bevel gear 29 is arranged at the upper end of the driving bevel gear 37 in a meshed manner, a moving shaft 28 is fixedly connected to the upper end of the sliding bevel gear 29, the upper end of the moving shaft 28 is in threaded connection with the sleeve 27, moving bevel gears 34 are symmetrically arranged at the left and right ends of the driving bevel gear 37 in a rotatable manner, the moving bevel gears 34 are meshed with the driving bevel gear 37, sliding screws 32 are fixedly connected to the ends of the moving bevel gears 34 far away from each other, moving cavities 31 are symmetrically arranged in the inner walls at the left and right sides of the transmission cavity 30 with opposite openings, ball screw nuts 33 are slidably arranged in the moving cavities 31 from left to right, the sliding screws 32 extend into the moving cavities 31 and are in threaded connection with the ball screw nuts 33, and sliding, the upper end of the sliding rod 43 is hinged with a sliding block 45, the front end of the sliding block 45 is fixedly connected with a moving rod 46, one end of the moving rod 46, which is far away from the transmission cavity 30, is fixedly connected with the positioning pin 49, a moving groove 44 is arranged in the inner wall of the rear side of the moving cavity 31 in a communicating manner, the sliding block 45 is arranged in the moving groove 44, and the moving groove 44 guides the sliding block 45 to slide, rotates the rotation shaft 41, thereby rotating the drive bevel gear 37 and thus the sliding bevel gear 29, thereby driving the sleeve 27 to slide up and down through the moving shaft 28, and simultaneously the drive bevel gear 37 rotates and drives the moving bevel gear 34 to rotate, the ball screw nut 33 is driven to slide left and right by the sliding screw 32, and the sliding block 45 is driven to slide left and right by the sliding rod 43, and the positioning pin 49 is driven to slide left and right by the moving rod 46.

The following describes in detail the use steps of a clamping and positioning fixture for a circular arc surface workpiece in the present text with reference to fig. 1 to 7:

initially, the vertical slider 22 is located at the lower limit position, at this time, the three support rods 14 are in a mutually close state, at this time, the fixed gripper 12 abuts against the movable gripper 13, at this time, the clamping spring 53 is in a normal state, at this time, the positioning pins 49 on both sides are in a mutually close state, and the fixed block 35, the sleeve 27 and the positioning clip 26 are completely accommodated in the accommodating cavity 50.

When the workpiece is a circular truncated cone workpiece, the adjusting screw rod 11 is rotated according to the diameter size of the circular truncated cone workpiece, so that the movable gripper 13 is driven to slide, the distance between the fixed gripper 12 and the movable gripper 13 is adjusted, the circular truncated cone workpiece is placed between the three pairs of fixed grippers 12 and the movable gripper 13, the fixed gripper 12 and the movable gripper 13 are attached to the surface of the workpiece, the workpiece is clamped under the elastic force of the clamping spring 53, and the upper end of the positioning pin 49 abuts against the planar end face of the circular truncated cone workpiece and positions the circular truncated cone workpiece;

when the workpiece is a conical workpiece, the positioning pin 49 is no longer suitable for positioning the vertex of the conical workpiece, at this time, according to the diameter size of the conical workpiece, the adjusting screw 11 is rotated to drive the movable gripper 13 to slide and adjust the distance between the fixed gripper 12 and the movable gripper 13, the conical workpiece is placed between three pairs of fixed grippers 12 and movable gripper 13, the fixed gripper 12 and the movable gripper 13 are attached to the surface of the workpiece, the workpiece is clamped under the elastic force of the clamping spring 53, the rotating shaft 41 is rotated to drive the driving bevel gear 37 to rotate, the sliding bevel gear 29 is rotated, the sleeve 27 is driven to slide upwards by the moving shaft 28, the driving bevel gear 37 is rotated to drive the moving bevel gear 34 to rotate, the ball screw nuts 33 are driven to slide towards both sides by the sliding screw 32, and the sliding blocks 45 are driven to slide towards both sides by the sliding rods 43, the moving rod 46 drives the positioning needle 49 to slide towards two sides, so that the vertex of the conical workpiece extends into the space between the positioning clamps 26 on two sides and pushes the positioning clamps 26 to swing, the conical workpiece is positioned when the swing angles of the positioning clamps 26 on two sides are the same, and the extension spring 36 is in an extension state;

the motor 25 is started, the vertical sliding block 22 is driven to slide up and down through the lifting screw 23, the connecting rod 21 is driven to swing to the side away from the vertical sliding block 22, the push rod 20 is driven to move to the side away from the vertical sliding block 22, the supporting rod 14 is driven to move to the side away from the vertical sliding block 22, the fixed gripper 12 and the movable gripper 13 are driven to move to the side away from the vertical sliding block 22, and therefore the fixed gripper 12 and the movable gripper 13 can clamp a workpiece.

In the above manner, a person skilled in the art can make various changes depending on the operation mode within the scope of the present invention.

Claims

1. The utility model provides a centre gripping positioning fixture for arc surface work piece, includes rolling disc and base, the rolling disc support in the base upper end, its characterized in that: three clamping devices are arranged on the upper side of the rotating disc, the clamping devices on the left side and the right side are positioned on the same horizontal plane, the clamping device on the rear side is higher than the clamping devices on the left side and the right side, the clamping device comprises a fixed gripper and a movable gripper, the movable gripper is positioned on one side of the fixed gripper in the clockwise direction, an adjusting screw rod is connected between the fixed gripper and the movable gripper through threads, the fixed gripper and the movable gripper are abutted against the circular arc surface of the circular truncated cone workpiece and clamp the circular truncated cone workpiece, a spring groove with an opening facing the fixed hand grip is arranged in the movable hand grip, one end of the fixed hand grip close to the movable hand grip is fixedly connected with a guide rod, the guide rod extends into the spring groove and is connected with the movable gripper in a sliding manner, and a clamping spring is fixedly connected between the guide rod and the inner wall of the spring groove; a cavity is formed in the rotating disc, a vertical sliding block is arranged in the cavity in a vertically sliding manner, three connecting rods are distributed on the peripheral surface of the vertical sliding block in an annular array manner and hinged to the peripheral surface of the vertical sliding block, a push rod is hinged to the upper end of each connecting rod, a supporting rod is hinged to one end, away from the vertical sliding block, of each push rod, and the upper ends of the three supporting rods are fixedly connected to the three fixed grippers respectively; the upper end of the rotating disc is connected with a positioning device, the positioning device comprises positioning needles which are bilaterally symmetrical, the positioning needles are connected to the rotating disc in a sliding mode, the upper end of the rotating disc is fixedly connected with a fixed block, the fixed block is located between the positioning needles on two sides, a containing cavity with an opening facing the fixed block is arranged in each positioning needle, a transmission cavity is arranged in each fixed block, a sliding guide cavity with an upward opening is arranged in each transmission cavity, a sleeve is arranged in each sliding guide cavity in a vertically sliding mode, the upper end of each sleeve extends out of the corresponding sliding guide cavity, the left end and the right end of each sleeve are symmetrical and hinged to a positioning clamp, and a tension spring is fixedly connected between the positioning; the inner wall of the upper side of the cavity is internally and communicatively provided with three guide grooves which take the vertical sliding block as a symmetric center and are distributed in an annular array, the openings of the guide grooves are upward, the three support rods respectively penetrate through the three guide grooves, the inner wall of the lower side of the cavity is internally and communicatively provided with three moving grooves which take the vertical sliding block as a symmetric center and are distributed in an annular array, the lower ends of the three support rods respectively extend into the three moving grooves, and a buffer spring is fixedly connected between one end of each support rod, far away from the vertical sliding block, and the inner wall of one side, far away from the vertical sliding block, of; the inner wall of the cavity is fixedly connected with three fixing rods which are distributed in an annular array mode by taking a vertical sliding block as a symmetrical center, sliding grooves with downward openings are formed in the lower sides of the three fixing rods, connecting blocks are arranged in the sliding grooves and slide in the sliding grooves, and the connecting blocks are hinged to one side, close to the center, of the push rod; a lifting screw rod is connected with the vertical sliding block in an internal thread mode, the lower end of the lifting screw rod is rotatably connected to the base, a motor is fixedly arranged in the base, and the lower end of the lifting screw rod is in power connection with the motor; a driving bevel gear is rotatably arranged in the transmission cavity, a rotating shaft is fixedly connected to the front end of the driving bevel gear, a sliding bevel gear is arranged at the upper end of the driving bevel gear in a meshed manner, a moving shaft is fixedly connected to the upper end of the sliding bevel gear, the upper end of the moving shaft is in threaded connection with the sleeve, moving bevel gears are symmetrically and rotatably arranged at the left and right ends of the driving bevel gear, the moving bevel gears are meshed with the driving bevel gear, a sliding screw rod is fixedly connected to the end, away from each other, of the moving bevel gears, moving cavities are symmetrically arranged in the inner walls at the left and right sides of the transmission cavity, the openings of the moving cavities are opposite, a ball screw nut is arranged in the moving cavity in a left-right sliding manner, the sliding screw rod extends into the moving cavity and is in threaded connection with the ball screw nut, a sliding, one end of the moving rod, which is far away from the transmission cavity, is fixedly connected with the positioning needle, a moving groove is formed in the inner wall of the rear side of the moving cavity in a communicating mode, and the sliding block is arranged in the moving groove.