阅读说明：本技术 一种用于金加工的分度盘工装 (Index plate tool for metalworking ) 是由 王成 李桂忠 卓剑勇 王新敏 李昕忠 柳刘 黄曰强 晏毅 郑友牙 黄海军 邬海金 于 2021-07-28 设计创作，主要内容包括：本发明公开了一种用于金加工的分度盘工装,其特征在于包括安装座、分度盘、工件夹持定位装置和分度指针,安装座与钻孔设备固定连接,分度盘插入安装座内孔中,与安装座形成可旋转连接,钻孔时通过T型螺栓将分度盘与安装座锁紧,所述圆盘外圆面上设有刻度线,分度指针固定连接于磁力座上,分度指针的针尖指向刻度线；分度盘上设有止口,用于工件定位,工件夹持定位装置用于将工件与分度盘固定连接。本发明通过工件与分度盘固定连接,可随分度盘一起旋转分度,使工件上多个呈圆周均布的孔只需调整一个孔的位置,通过分度盘旋转分度,即可完成所有孔加工,不需要每个孔位单独调整位置,工作效率高,定位精度高,同时降低了操作人员的劳动强度。(The invention discloses an index plate tool for metalworking, which is characterized by comprising an installation seat, an index plate, a workpiece clamping and positioning device and an index pointer, wherein the installation seat is fixedly connected with drilling equipment; the indexing disc is provided with a spigot for positioning a workpiece, and the workpiece clamping and positioning device is used for fixedly connecting the workpiece with the indexing disc. The workpiece is fixedly connected with the index plate and can rotate and index along with the index plate, so that the holes uniformly distributed on the circumference of the workpiece can be machined by only adjusting the position of one hole and rotating and indexing the index plate, and each hole position does not need to be independently adjusted, so that the working efficiency is high, the positioning precision is high, and the labor intensity of operators is reduced.)

1. The index plate tool for metalworking is characterized by comprising an installation seat, an index plate, a workpiece clamping and positioning device and an index pointer, wherein the installation seat is detachably and fixedly connected with a drilling equipment workbench, a first through hole is formed in the middle of the installation seat, a first counter bore is formed in the upper end of the first through hole, a rolling bearing is arranged in the first counter bore, an annular T-shaped groove coaxial with the first through hole is formed in the upper end face of the installation seat, a plurality of blind holes which are uniformly distributed circumferentially and take the axis of the first through hole as the center are further formed in the outer side of the annular T-shaped groove in the upper end face of the installation seat, wear-resistant steel balls are arranged in the blind holes, and the highest point of each wear-resistant steel ball is 0.5-1 mm higher than the upper end face of the installation seat;

the indexing disc is coaxial with the mounting seat and comprises a first spigot, a first boss, a disc and a second boss which are sequentially connected from top to bottom, a second through hole is formed in the middle of the indexing disc, the outer diameter of the first spigot is matched with the inner diameter of an inner hole at the lower end of a workpiece, the outer circular surface of the second boss is fastened with the inner ring of the rolling bearing, the indexing disc is rotatably connected with the mounting seat, two third through holes which are distributed in a central symmetry mode are formed in the upper end face of the disc, the positions of the third through holes correspond to the positions of the annular T-shaped grooves, two T-shaped bolts penetrate through the two third through holes respectively and are sleeved with first locking nuts, the indexing disc and the mounting seat are locked during drilling, scale marks are arranged on the outer circular face of the disc, and the scale interval between every two adjacent scale marks is 1-5 degrees;

the indexing pointer is fixedly connected to the magnetic base, the magnetic base is arranged on the outer side of the mounting base, and the needle point of the indexing pointer points to the scale mark;

the workpiece clamping and positioning device comprises a shouldered screw rod, a thick washer, a second locking nut and a pressing plate, wherein the pressing plate is arranged at the upper end of the workpiece and used for pressing the workpiece, a fourth through hole is formed in the middle of the pressing plate, the shouldered screw rod sequentially penetrates through the second through hole, a workpiece inner hole, the fourth through hole, the thick washer and the second locking nut from bottom to top, and the workpiece is fixedly connected with the index plate by screwing the second locking nut.

2. The index plate tooling for metalworking of claim 1, wherein: the upper end of the second through hole is provided with a second counter bore, the lower end of the second through hole is provided with a third counter bore, and the shoulder of the screw rod with the shoulder is arranged in the third counter bore.

3. The index plate tooling for metalworking of claim 2, wherein: the workpiece clamping and positioning device further comprises a three-jaw chuck, three jaws of the three-jaw chuck expand tightly on the inner circular surface of the inner hole of the workpiece, the inner hole at the lower end of the three-jaw chuck is sleeved with the first spigot, the pressing plate is in a three-fork shape and is arranged on the upper plane of the three jaws, and the three-jaw chuck is fixedly connected with the index plate.

4. The index plate tooling for metalworking of claim 3, wherein: the three claws of the three-claw chuck are lengthened three claws.

5. The index plate tooling for metalworking of claim 2, wherein: a plurality of seam allowances are further arranged on the upper end face of the disc and outside the first boss, and the outer diameters of the seam allowances are respectively matched with the inner diameters of inner holes at the lower ends of different workpieces.

6. The index plate tooling for metalworking of claim 5, wherein: the minimum clearance between the first locking nut and the outer circular surface of the first boss is set to be 10-15 mm.

7. The index plate tooling for metalworking according to any one of claims 1 to 6, wherein: the lower end face of the T-shaped bolt is a spherical surface.

8. The index plate tooling for metalworking according to any one of claims 1, 2 and 5, wherein: and one side of the fourth through hole is opened to form an open slot.

Technical Field

The invention relates to the technical field of machining, in particular to an index plate tool for machining a plurality of holes uniformly distributed on the circumference of a large-scale disc type or cylinder type workpiece on a drilling machine or a boring machine.

Background

When the end face drilling and tapping are carried out on some large-sized disc or cylinder parts, the end face drilling and tapping are generally realized by adopting a numerical control drilling machine or a common drilling machine. Although the numerical control drilling machine has high working efficiency, the cost is extremely high, and not all processing enterprises can pay high cost to purchase. And adopt ordinary drilling machine to drill, because screw hole or through-hole of a plurality of circumference equipartitions need be processed simultaneously to general disc or drum terminal surface, the tradition adds the line of need earlier in disc class or drum class part terminal surface, then through adjustment workstation position, drill one by one through the drilling machine, every aperture all needs the independent adjustment position, machining efficiency is extremely low, simultaneously when needs tapping, generally change the drill bit after the through-hole processing has been accomplished, then tap one by one, when carrying out batch production, to operating personnel, the amount of labour is big, low efficiency.

At present, when a plurality of threaded holes which are uniformly distributed in a circumferential mode are formed in the outer circular surface of some large-sized cylindrical parts, in the traditional machining process, the center positions of the uniformly distributed holes are usually drawn on a workpiece firstly, then a drilling machine is used for drilling each central hole, and the holes need to be clamped again after one hole is machined.

Disclosure of Invention

In order to solve the above background technical problems, the invention provides an index plate tool for metalworking, the tool can complete other circumferentially and uniformly distributed hole machining by only adjusting the position of one hole and rotating and indexing the index plate, the position of each hole is not required to be independently adjusted, the working efficiency is high, the positioning precision is high, and the labor intensity of operators is reduced.

In order to achieve the purpose, the invention provides the following technical scheme:

the index plate tool for metalworking is characterized by comprising an installation seat, an index plate, a workpiece clamping and positioning device and an index pointer, wherein the installation seat is detachably and fixedly connected with a drilling equipment workbench, a first through hole is formed in the middle of the installation seat, a first counter bore is formed in the upper end of the first through hole, a rolling bearing is arranged in the first counter bore, an annular T-shaped groove coaxial with the first through hole is formed in the upper end face of the installation seat, a plurality of blind holes which are uniformly distributed circumferentially and take the axis of the first through hole as the center are further formed in the outer side of the annular T-shaped groove in the upper end face of the installation seat, wear-resistant steel balls are arranged in the blind holes, and the highest point of each wear-resistant steel ball is 0.5-1 mm higher than the upper end face of the installation seat;

the indexing disc is coaxial with the mounting seat and comprises a first spigot, a first boss, a disc and a second boss which are sequentially connected from top to bottom, a second through hole is formed in the middle of the indexing disc, the outer diameter of the first spigot is matched with the inner diameter of an inner hole at the lower end of a workpiece, the outer circular surface of the second boss is fastened with the inner ring of the rolling bearing, the indexing disc is rotatably connected with the mounting seat, two third through holes which are distributed in a central symmetry mode are formed in the upper end face of the disc, the positions of the third through holes correspond to the positions of the annular T-shaped grooves, two T-shaped bolts penetrate through the two third through holes respectively and are sleeved with first locking nuts, the indexing disc and the mounting seat are locked during drilling, scale marks are arranged on the outer circular face of the disc, and the scale interval between every two adjacent scale marks is 1-5 degrees;

the indexing pointer is fixedly connected to the magnetic base, the magnetic base is arranged on the outer side of the mounting base, and the needle point of the indexing pointer points to the scale mark;

the workpiece clamping and positioning device comprises a shouldered screw rod, a thick washer, a second locking nut and a pressing plate, wherein the pressing plate is arranged at the upper end of the workpiece and used for pressing the workpiece, a fourth through hole is formed in the middle of the pressing plate, the shouldered screw rod sequentially penetrates through the second through hole, a workpiece inner hole, the fourth through hole, the thick washer and the second locking nut from bottom to top, and the workpiece is fixedly connected with the index plate by screwing the second locking nut.

Furthermore, a second counter bore is formed in the upper end of the second through hole, a third counter bore is formed in the lower end of the second through hole, and the shoulder of the screw rod with the shoulder is arranged in the third counter bore.

Furthermore, the workpiece clamping and positioning device further comprises a three-jaw chuck, three jaws of the three-jaw chuck are expanded on the inner circular surface of the inner hole of the workpiece, the inner hole at the lower end of the three-jaw chuck is sleeved with the first spigot, the pressing plate is in a three-fork shape and is arranged on the upper plane of the three jaws, and the three-jaw chuck is fixedly connected with the index plate.

Furthermore, the three claws of the three-claw chuck are lengthened three claws. The lengthened three claws are used for expanding the workpiece with a larger inner hole.

Furthermore, a plurality of seam allowances are further arranged on the outer side of the first boss on the upper end face of the disc, and the outer diameters of the seam allowances are respectively matched with the inner diameters of inner holes at the lower ends of different workpieces. Further, the minimum clearance between the first locking nut and the outer circular surface of the first boss is set to be 10-15 mm. The first locking nut is convenient for an operator to lock or loosen by using a lengthened sleeve wrench, so that interference is avoided.

Further, the lower end face of the T-shaped bolt is a spherical surface. The friction between the T-shaped bolt and the bottom of the annular T-shaped groove can be effectively reduced when the indexing disc rotates, so that an operator can rotate more easily.

Furthermore, one side of the fourth through hole is opened to form an open groove. The open slot is formed in the pressing plate, the second locking nut only needs to be unscrewed, the pressing plate can be taken down from the side face, the time for completely taking the second locking nut and the thick washer is saved, the workpiece can be clamped more conveniently, and the working efficiency is improved.

Compared with the prior art, the invention has the beneficial effects that: 1) by arranging the index plate and the mounting seat, the workpiece is fixedly connected with the index plate and can rotate and index along with the index plate, so that the holes uniformly distributed on the workpiece in the circumferential direction can be machined by only adjusting the position of one hole and rotating and indexing the index plate, the position of each hole is not required to be independently adjusted, the working efficiency is high, and the labor intensity of operators is reduced; 2) the lower ends of the steel balls and the T-shaped bolts are arranged to be spherical surfaces, so that the friction force of the indexing disc during rotation is reduced, an operator can rotate the indexing disc more conveniently and more labor-saving, the working efficiency is improved, and the service life of the tool is prolonged; 3) the rabbets with different outer diameters are arranged on the index plate, so that the tool can be used for processing parts with different specifications and different shapes, the manufacturing cost of multiple sets of tools is saved, and the practicability is high.

Drawings

FIG. 1 is a schematic structural diagram of an embodiment of the present invention;

FIG. 2 is a top view of the present invention;

FIG. 3 is a schematic cross-sectional view of a mounting base according to an embodiment of the invention;

FIG. 4 is a top view of FIG. 3;

FIG. 5 is a schematic cross-sectional view of an index plate according to an embodiment of the present invention;

FIG. 6 is a schematic view of an outer structure of an index plate according to an embodiment of the present invention;

FIG. 7 is a schematic view of a T-bolt structure;

FIG. 8 is a schematic view of a platen configuration;

FIG. 9 is a schematic structural diagram according to a second embodiment of the present invention;

FIG. 10 is a top view of the second embodiment of the present invention;

FIG. 11 is a schematic view of a second platen according to an embodiment of the present invention;

FIG. 12 is a diagram illustrating a state of drilling a hole in an outer circular surface of an upper end of a workpiece according to an embodiment of the present invention;

FIG. 13 is a schematic view of a three-division dial according to an embodiment of the present invention;

FIG. 14 is a diagram illustrating a state of drilling holes in the outer circumferential surface of the lower end of three workpieces according to an embodiment of the present invention.

In the figure: 1. the first workpiece, 1 ', the second workpiece, 1', the third workpiece, 2, the three-jaw chuck, 201, the lengthened three-jaw, 3, the index plate, 301, the second through hole, 302, the second counter bore, 303, the first spigot, 304, the first boss, 305, the third through hole, 306, the second spigot, 307, the disc, 308, the second boss, 309, the third counter bore, 310, the scale mark, 311, the third spigot, 4, the mounting seat, 401, the first through hole, 402, the first counter bore, 403, the annular T-shaped groove, 404, the blind hole, 405, the stepped open slot, 5, the pressing plate, 501, the fourth through hole, 5 ', the pressing plate, 501', the open slot, 6, the screw with shoulder, 7, the thick washer, 8, the second lock nut, 9, the T-shaped bolt, 901, the spherical surface, 10, the first lock nut, 11, the rolling bearing, 12, the wear-resistant steel ball, 13, the index pointer, 14, and the magnetic seat.

Detailed Description

In the description of the present invention, it is to be understood that the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", "vertical", "horizontal", and the like, indicate orientations or positional relationships based on those shown in the drawings, are merely for convenience of description and simplicity of description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed in a particular orientation, and be operated, and thus, are not to be construed as limiting the present invention.

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments.

As shown in fig. 1 to 8, the embodiment of the invention is used for machining multiple holes on the upper end surface of a large disc-like workpiece 1 with a larger inner diameter, and comprises a mounting seat 4, an index plate 3, a workpiece clamping and positioning device and an index pointer 13. The mounting seat 4 is detachably and fixedly connected with a drilling machine workbench through bolts and a stepped open slot 405, a first through hole 401 is arranged in the middle of the mounting seat 4, a first counter bore 402 is arranged at the upper end of the first through hole 401, a rolling bearing 11 is arranged in the first counter bore 401, an annular T-shaped groove 403 coaxial with the first through hole 401 is arranged on the upper end surface of the mounting seat 4, 6 blind holes 404 which are uniformly distributed circumferentially and centering on the axis of the first through hole 401 are also arranged on the outer side of the annular T-shaped groove 403 on the upper end surface of the mounting seat 4, wear-resistant steel balls 12 are arranged in the blind holes 404, and the highest point of each wear-resistant steel ball 12 is 1mm higher than the upper end surface of the mounting seat 4;

the dividing plate 3 is coaxial with the mounting base 4 and comprises a first spigot 303, a first boss 304, a disc 307 and a second boss 308 which are sequentially connected from top to bottom, a second through hole 301 is arranged in the middle of the dividing plate, a second counter bore 302 is arranged at the upper end of the second through hole 301, a third counter bore 309 is arranged at the lower end of the second through hole 301, the outer circular surface of the second boss 304 is fastened with the inner ring of the rolling bearing 11, so that the dividing plate 3 and the mounting base 4 are rotatably connected, two third through holes 305 which are symmetrically distributed in the center are arranged on the upper end surface of the disc 307, the third through hole 305 corresponds to the annular T-shaped groove 403, two T-shaped bolts 9 are arranged in the annular T-shaped groove 403 and respectively pass through the two third through holes 305, a first locking nut 10 is sleeved at the upper end of each T-shaped bolt 9, the hole-drilling indexing mechanism is used for locking the indexing disc 3 and the mounting base 4 during hole drilling, the outer circle surface of the disc 307 is provided with scale marks 310, and the scale value between every two adjacent scale marks is 5 degrees;

the lower end surface of the T-shaped bolt 9 is a spherical surface 901, so that the friction between the T-shaped bolt 5 and the bottom of the annular T-shaped groove 403 can be effectively reduced when the indexing disc 3 rotates, and an operator can rotate more easily.

The indexing pointer 13 is fixedly connected to the magnetic base 14, the magnetic base 14 is arranged on the outer side of the mounting base 4, and the needle point of the indexing pointer 13 points to the scale mark 310;

the workpiece clamping and positioning device comprises a screw rod 6 with a shoulder, a thick washer 7, a second locking nut 8, a three-jaw chuck 2 and a pressing plate 5, wherein the three-jaw 201 of the three-jaw chuck 2 expands on the inner circular surface of an inner hole of a workpiece 1, the three-jaw 201 of the three-jaw chuck 2 is an elongated three-jaw, the inner hole of the lower end of the three-jaw chuck 2 is matched with the outer diameter of a first spigot 303, the inner hole of the lower end of the three-jaw chuck 2 is sleeved with the first spigot 303, the pressing plate 5 is in a three-fork shape and is arranged on the upper plane of the three-jaw 201, a fourth through hole 501 is arranged in the middle of the pressing plate 5, the shoulder of the screw rod 6 with the shoulder is arranged in a third counter bore 309, the shoulder sequentially penetrates through the second through hole 301, the inner hole of the workpiece 1, the fourth through hole 501, the thick washer 7 and the second locking nut 8 from bottom to top, and the three-jaw chuck 2 is fixedly connected with a dividing plate 3 by screwing the second locking nut 8.

The working principle of the embodiment is as follows: drawing circle center lines to be drilled on the upper plane of a workpiece, supporting three claws of a three-claw chuck to inner holes of the workpiece, aligning the upper plane of the workpiece, keeping the upper plane of the workpiece horizontal, then expanding the three claws to fix the workpiece, placing a pressing plate 5 above the three claws, screwing a second locking nut 8 to fixedly connect the three-claw chuck 2 with an index plate 3, directing an index pointer to 0 scale line position, screwing a first locking nut 10, locking the index plate 3 with a mounting seat 4, moving a drill bit to the circle center lines, drilling a first hole, then loosening the first locking nut 10, rotating the index plate 3 to direct the index pointer to the next hole scale line position, then locking the first locking nut 10, drilling a second hole, and so on, so as to accurately position all the holes step by step, saving a large amount of hole-drawing bit lines, aligning the time of the drill bit to the hole bit lines, greatly improving the working efficiency and improving the positioning accuracy, and simultaneously, the labor intensity of operators is reduced.

As shown in fig. 9, 10 and 11, the embodiment of the invention is used for machining multiple holes on the upper end surface of a large disc-like workpiece 1' with a smaller inner diameter, and comprises a mounting seat 4, an index plate 3, a workpiece clamping and positioning device and an index pointer 13. The mounting seat 4 is detachably and fixedly connected with a drilling machine workbench through bolts and a stepped open slot 405, a first through hole 401 is arranged in the middle of the mounting seat 4, a first counter bore 402 is arranged at the upper end of the first through hole 401, a rolling bearing 11 is arranged in the first counter bore 401, an annular T-shaped groove 403 coaxial with the first through hole 401 is arranged on the upper end surface of the mounting seat 4, 6 blind holes 404 which are uniformly distributed circumferentially and centering on the axis of the first through hole 401 are also arranged on the outer side of the annular T-shaped groove 403 on the upper end surface of the mounting seat 4, wear-resistant steel balls 12 are arranged in the blind holes 404, and the highest point of each wear-resistant steel ball 12 is 1mm higher than the upper end surface of the mounting seat 4;

the dividing plate 3 is coaxial with the mounting seat 4 and comprises a first spigot 303, a first boss 304, a disc 307 and a second boss 308 which are sequentially connected from top to bottom, a second through hole 301 is arranged in the middle of the dividing plate, a second counter bore 302 is arranged at the upper end of the second through hole 301, a third counter bore 309 is arranged at the lower end of the second through hole 301, the outer diameter of the first spigot 303 is matched with the inner diameter of an inner hole of the second 1' of the workpiece, the outer circular surface of the second boss 304 is fastened with the inner ring of the rolling bearing 11, so that the dividing plate 3 is rotatably connected with the mounting seat 4, two third through holes 305 which are symmetrically distributed in the center are arranged on the upper end surface of the disc 307, the positions of the third through holes 305 correspond to the positions of the annular T-shaped grooves 403, two T-shaped bolts 9 are arranged in the annular T-shaped grooves 403 and respectively penetrate through the two third through holes 305, a first locking nut 10 is sleeved on the upper end of each T-shaped bolt 9 and used for locking the dividing plate 3 and the mounting seat 4 during drilling, and scale marks 310 are arranged on the outer circular surface of the disc 307, the scale value between every two adjacent scale marks is 2 degrees;

the lower end surface of the T-shaped bolt 9 is a spherical surface 901, so that the friction between the T-shaped bolt 5 and the bottom of the annular T-shaped groove 403 can be effectively reduced when the indexing disc 3 rotates, and an operator can rotate more easily.

The indexing pointer 13 is fixedly connected to the magnetic base 14, the magnetic base 14 is arranged on the outer side of the mounting base 4, and the needle point of the indexing pointer 13 points to the scale mark 310;

the workpiece clamping and positioning device comprises a screw rod 6 with a shoulder, a thick washer 7, a second locking nut 8 and a pressing plate 5 ', an inner hole of a second workpiece 1' is sleeved on the first spigot 303, the pressing plate 5 'is arranged at the upper end of the second workpiece 1' and used for pressing the second workpiece 1 ', an open groove 501' is formed in the middle of the pressing plate 5 ', the shoulder of the screw rod 6 with the shoulder is arranged in a third counter bore 309 and sequentially penetrates through a second through hole 301, the inner hole of the second workpiece 1', the open groove 501 ', the thick washer 7 and the second locking nut 8 from bottom to top, and the second workpiece 1' and the index plate 3 are fixedly connected by screwing the second locking nut 8.

The working principle of the embodiment is as follows: the method comprises the steps of marking a to-be-drilled hole circular center line on the upper plane of a workpiece, sleeving an inner hole of a second workpiece 1 'on a first spigot 303, pressing a plate 5' on the upper end face of the second workpiece 1 ', screwing a second locking nut 8 to fixedly connect the second workpiece 1' with an index plate 3, enabling an index pointer to point to 0 scale mark position, screwing a first locking nut 10, locking the index plate 3 and a mounting seat 4, moving a drill bit to a circle center line, drilling a first hole, then loosening the first locking nut 10, rotating the index plate 3 to enable the index pointer to point to the next hole scale mark position, then locking the first locking nut 10, drilling a second hole, and so on in sequence, so that all holes can be drilled out in a step-by-step accurate positioning mode, a large number of hole drilling bit lines are saved, the time for aligning the drill bit to the hole bit lines is shortened, the working efficiency is greatly improved, the positioning accuracy is improved, and the labor intensity of operators is reduced.

As shown in fig. 12, 13 and 14, the three-purpose device of the embodiment of the invention is used for a plurality of holes which are uniformly distributed on the outer circular surface of the upper end and the lower end of a workpiece three 1 "(shield machine base) in a radial direction in a circumferential direction, and is basically the same as the second embodiment, except that the mounting base 4 is detachably and fixedly connected with a boring machine workbench through bolts and a stepped open slot 405.

The upper end face of the circular disc 307 of the dividing disc 3 is also provided with a second spigot 306 and a third spigot 311 outside the first boss 304, the outer diameter of the second spigot 306 is matched with the inner diameter of the inner hole at the lower end of the third workpiece 1 ', and the outer diameter of the third spigot 311 is matched with the inner diameter of the inner hole at the upper end of the third workpiece 1'.

The minimum clearance between the first lock nut 10 and the outer circular surface of the first boss 304 is set to be 10-15 mm. The first locking nut 10 is convenient for an operator to lock or loosen by using a lengthened sleeve wrench, and interference is avoided.

The working principle of the embodiment is as follows: the height line to be drilled is marked on the outer circular surface of the upper end and the lower end of a workpiece by using a height gauge, an inner hole at the lower end of the workpiece III 1 is sleeved on a second spigot 306, a pressing plate is arranged on the upper end surface of the workpiece III 1, a second locking nut 8 is screwed to fixedly connect the workpiece III 1 with an indexing disc 3, an indexing pointer points to the position of 0 scale mark, a first locking nut 10 is screwed to lock the indexing disc 3 with a mounting seat 4, a drill bit is moved to the height line at the upper end of the workpiece III 1 to drill a first hole, then the first locking nut 10 is loosened by a panel of an extension sleeve, the indexing disc 3 is rotated to enable the indexing pointer to point to the position of the next hole scale mark, the first locking nut 10 is locked by the panel of the extension sleeve to drill a second hole, and so on, holes drilled on the outer circular surface of the upper end of the workpiece III 1 can be accurately positioned step by step.

Loosening the second locking nut 8, taking down the workpiece III 1 'to turn around, sleeving an inner hole at the upper end of the workpiece III 1' on the third spigot 311, pressing a plate on the upper end face of the workpiece III 1 ', screwing the second locking nut 8 to fixedly connect the workpiece III 1' with the dividing plate 3, enabling the dividing pointer to point to the 0-scale-mark position, screwing the first locking nut 10, locking the dividing plate 3 with the mounting seat 4, moving the drill bit to the height line of the lower end of the workpiece III 1 ', drilling a first hole, loosening the first locking nut 10 by using the extension sleeve, rotating the dividing plate 3 to enable the dividing pointer to point to the next-hole scale-mark position, locking the first locking nut 10 by using the extension sleeve, drilling a second hole, and so on, and accurately positioning step by step to drill out all holes on the outer circle face of the lower end of the workpiece III 1'.

The embodiment of the invention saves a large amount of time for scribing bit lines and aligning the bit lines, greatly improves the working efficiency, improves the positioning precision and simultaneously reduces the labor intensity of operators.

Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that changes, modifications, substitutions and alterations can be made in these embodiments without departing from the principles and spirit of the invention, the scope of which is defined in the appended claims and their equivalents.