CN106493463B - A kind of machining equipment being able to achieve any angle cutting - Google Patents

Abstract

The invention discloses a kind of machining equipments for being able to achieve any angle cutting, including mobile support saddle, vertical stand, crossbeam, sliding sleeve, mounting plate, lifting motor, elevating screw, cutting head, the mobile support saddle is mounted on the rack, the vertical stand is welded on mobile support saddle vertically, and sliding slot is provided in vertical stand, the sliding sleeve is slidably connected in vertical stand by sliding slot, and the threaded hole of vertical direction is provided on sliding sleeve, the crossbeam level is welded on sliding sleeve side, the mounting plate is fixed at the top of vertical stand, the elevating screw upper and lower ends are connected to mounting plate by bearing block, on mobile support saddle, and elevating screw is connect by screw thread with sliding sleeve, the lifting motor is affixed on a mounting board, and lifting motor output shaft and elevating screw are affixed, the cutting head is mounted on the top of crossbeam End.The present invention has many advantages, such as that structure is simple, stable, precision is high, reduces production cost.

Description

A mechanical processing equipment capable of cutting at any angle

technical field

The invention relates to the technical field of machine cutting equipment, in particular to a mechanical processing equipment capable of cutting at any angle.

Background technique

Plasma cutting with different working gases can cut various metals that are difficult to cut by oxygen cutting, especially for non-ferrous metals (stainless steel, aluminum, copper, titanium, nickel), the cutting effect is better; its main advantage is that the cutting thickness of metals is not large. At times, the plasma cutting speed is fast, especially when cutting ordinary carbon steel sheets, the speed can reach 5 to 6 times that of the oxygen cutting method, the cutting surface is smooth, the thermal deformation is small, and the heat affected zone is less. Plasma cutting machines are widely used in automobiles, locomotives, pressure vessels, chemical machinery, nuclear industry, general machinery, construction machinery, steel structures, ships and other industries.

In order to improve production efficiency and reduce labor costs, many companies use automated cutting robots for cutting operations. However, most of the existing cutting robots use oil cylinders and motor gears as power for telescopic and rotation. This form of drive is stable and reliable. There are defects in accuracy, which will limit the quality of the workpiece to be processed. At the same time, for the existing workpiece, the cutting angle is very important, and the required angle can be cut at one time, which will greatly reduce the production cost.

When a Chinese patented cutting or welding robot (application number 201110033209.4) is used, the requirement for the cutting angle can only ensure that the cutting angle is vertical. For the current part processing requirements, this technology has been difficult to meet the current needs, which is also The common problems of the existing cutting machines are that the existing methods are secondary or even multiple processing, which will greatly increase the production cost.

SUMMARY OF THE INVENTION

The technical problem to be solved by the present invention is to overcome the defects of the prior art and provide a mechanical processing device capable of cutting at any angle.

In order to solve the above-mentioned technical problems, the present invention provides the following technical solutions: a mechanical processing equipment capable of cutting at any angle, including a mobile support, a vertical frame, a beam, a sliding sleeve, a mounting plate, a lifting motor, a lifting screw, a cutting The moving support is installed on the frame, the vertical frame is installed on the moving support, and the vertical frame is provided with a chute, and the sliding sleeve is slidably connected to the vertical through the chute. The sliding sleeve is provided with threaded holes in the vertical direction, the beam is horizontally connected to one side of the sliding sleeve, the mounting plate is fixed on the top of the vertical frame, and the upper and lower ends of the lifting screw The bearing seat is connected to the mounting plate and the moving support respectively, and the lifting screw is connected to the sliding sleeve through the thread, the lifting motor is fixed on the mounting plate, and the output shaft of the lifting motor is fixed to the lifting screw, so The described cutting head is mounted on the end of the beam.

Further, the moving support includes a fixed plate, a transverse sliding rod, a transverse screw, a transverse motor, a transverse sliding block, a longitudinal sliding rod, a longitudinal screw, a longitudinal motor and a longitudinal sliding block, and the fixing plate is two. The two fixed plates are arranged in parallel, and the two lateral sliding rods are set in groups, and the two ends of the lateral sliding rod are respectively fixed on the fixed plate. There are threaded holes on it, the two ends of the horizontal screw rod are mounted on the fixed plate through the bearing seat, and the horizontal screw rod is connected with the horizontal slider through the screw thread, the horizontal motor is fixed on the fixed plate, and the horizontal motor The output shaft is fixedly connected with the transverse screw rod, the two ends of the longitudinal sliding rod are fixedly connected with the two transverse sliding blocks, the longitudinal sliding blocks are slidably connected to the longitudinal sliding rod, and the longitudinal sliding block is provided with threaded holes, and the longitudinal sliding blocks are provided with threaded holes. The slider is fixedly connected with the vertical frame, the two ends of the longitudinal screw rod are installed on the two lateral sliders through the bearing seat, and the longitudinal screw rod and the longitudinal slider are connected by threads, and the longitudinal motor is installed on the lateral slider and the longitudinal motor output shaft is fixedly connected with the longitudinal screw rod.

Further, the cutting head is composed of a rotating head, a mounting frame and a cutting torch head, the mounting frame is connected to the rotating head, and the cutting torch head is fixed in the mounting frame.

Further, the rotating head includes a bearing mounting seat, a rotating shaft, a rotating gear and a rotating motor, the bearing mounting seat is fixed on the end of the beam, the rotating shaft is mounted in the bearing mounting seat, and the rotating gear It is fixed on the upper part of the rotating shaft, the rotating motor is fixed on the bearing mounting seat through the bracket, and the output shaft of the rotating motor is meshed with the rotating gear through the gear.

Further, the mounting frame includes a bracket, a pin block, a fixed head and a swing cylinder, the bracket is L-shaped, the pin block is fixed on the end of the horizontal section of the bracket, and the fixed head is The middle part is welded on the pin shaft block, one end of the swing cylinder is fixed on the bracket through the pin shaft, and the other end is fixed on the upper part of the fixed head through the pin shaft.

Further, the fixing head includes two semi-circular fixing pieces, one side of the two semi-circular fixing pieces is connected by a pin shaft, and the other side is welded with a fixing ring, and the fixing bolt passes through the fixing ring to fix the Two semi-circular fixing pieces are connected into one body.

Further, the beam is divided into two parts: a rear tube and a front tube, the front tube is slidably connected to the inside of the rear tube through a chute, and a telescopic oil cylinder is fixedly connected to the inside of the rear tube. The front end of the rod is fastened to the front tube.

Further, the semicircular fixing piece is made of heat-resistant material.

Further, the lifting motor, the horizontal motor, the vertical motor, the swinging cylinder, the rotating motor and the telescopic oil cylinder are controlled by the same controller.

Further, the brackets can be replaced with L-shaped brackets of different proportions according to the needs of processing workpieces.

Further, the cutting gun head is a plasma cutting machine gun head, and the cutting gun head includes a gun head, an electrode, a shunt, a contact nozzle and a protective cover, and the cutting gun head is fixed in two semicircular fixed pieces. , the cutting gun head is connected with the plasma cutting machine through the connecting pipe, the electrode is installed in the cutting gun head, the shunt is installed in the cutting gun head, the contact tip is installed in the cutting gun head, the The protective cover is fixed on the bottom end of the cutting torch head.

Compared with the prior art, the present invention has the beneficial effects that the motor drives the screw rod to drive the sliding block to move, and the operation is more stable than the traditional driving mode of the oil cylinder and the motor gear, and the processing is greatly improved. It adopts integrated control system, which is easy to operate and easy to use; it can be cut at any angle in the cutting direction, and it can be cut at one time, which greatly reduces the production cost.

The invention uses the lifting motor to drive the lifting screw to rotate, so as to drive the sliding sleeve to change its position up and down, that is, the cutting head can move up and down in the vertical direction; The horizontal movement on the horizontal plane is to move the cutting head left and right on the horizontal plane; the longitudinal motor drives the vertical screw to rotate, thereby driving the vertical slider to move back and forth in the vertical direction on the horizontal plane, that is, the cutting head moves The changing action of moving back and forth in the longitudinal direction on the horizontal plane; the swing cylinder pushes the fixed head to rotate around the bracket through its own expansion and contraction, thereby changing the angle of the fixed head on the vertical plane, that is, the changing action of making the cutting head swing on the vertical plane ; The rotating motor drives the rotating shaft to rotate through the gear and the rotating gear, so that the cutting head rotates with the rotating shaft as the axis, that is, the changing action of making the cutting head rotate in the vertical direction; The length can meet the processing needs of different workpieces; through the above four action changes and one adjustment change, the cutting head can move freely and change the cutting angle, and the cutting angle has a wide range. This structure solves the problem of limited cutting angle in the prior art Therefore, the trouble of secondary or even multiple processing is eliminated, and the cost of product workpieces is greatly reduced.

The invention has the advantages of simple structure, stable operation, high precision, and reduced production cost.

Description of drawings

Fig. 1 is the basic structure schematic diagram of the present invention;

Fig. 2 is the structural representation of the mobile support in the present invention;

Fig. 3 is the structural representation of cutting head part in the present invention;

Fig. 4 is the structure schematic diagram of the fixed head in the present invention;

Fig. 5 is the structural schematic diagram of the beam part in the present invention;

Figure 6 is a schematic diagram of the structure of the cutting torch head part in the present invention;

The symbols in the figure are: 1-moving support; 2-vertical frame; 3-beam; 4-sliding sleeve; 5-installation plate; 6-lifting motor; 7-lifting screw; 8-cutting head; 9-rotation head; 10-mounting frame; 11-cutting torch head;

21-fixed plate; 22-transverse sliding rod; 23-transverse screw rod; 24-transverse motor; 25-transverse slider; 26-longitudinal sliding rod; 27-longitudinal screw; 28-longitudinal motor; 29-longitudinal slider ;

31-bearing mounting seat; 32-rotating shaft; 33-rotating gear; 34-rotating motor; 35-support; 36-pin block; 37-fixed head; 38-oscillating cylinder;

41-semi-circular fixing piece; 42-fixing ring; 43-fixing bolt;

51-rear pipe; 52-front pipe; 53- telescopic cylinder;

61- gun tip; 62- electrode; 63- shunt; 64- contact tip; 65- protective cover; 66- connecting pipe; 67- plasma cutting machine.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention.

As shown in Figure 1, a machining equipment capable of cutting at any angle includes a frame, a mobile support 1, a vertical frame 2, a beam 3, a sliding sleeve 4, a mounting plate 5, a lifting motor 6, and a lifting screw 7. Cutting head 8, the moving support 1 is installed on the frame, the vertical frame 2 is vertically welded on the moving support 1, and the vertical frame 2 is provided with a chute, the The sliding sleeve 4 is slidably connected to the vertical frame 2 through the sliding groove, and the sliding sleeve 4 is provided with threaded holes along the vertical direction, the beam 3 is flat welded on one side of the sliding sleeve 4, and the mounting plate 5 is fixedly connected On the top of the vertical frame 2, the upper and lower ends of the lifting screw 7 are respectively connected to the mounting plate 5 and the moving support 1 through bearing seats, and the lifting screw 7 is connected to the sliding sleeve 4 through threads. The motor 6 is fixedly connected to the mounting plate 5 , and the output shaft of the lifting motor 6 is fixedly connected to the lifting screw 7 , and the cutting head 8 is installed on the top end of the beam 3 .

As shown in FIG. 2, the moving support 1 is composed of a fixed plate 21, a transverse sliding rod 22, a transverse screw rod 23, a transverse motor 24, a transverse sliding block 25, a longitudinal sliding rod 26, a longitudinal screw rod 27, a longitudinal motor 28 and a longitudinal sliding rod 29, there are two fixed plates 21, the two fixed plates 21 are arranged in parallel, the two lateral sliding rods 22 are in a group, and the two ends of the lateral sliding rods 22 are respectively fixed on the fixed plate 21. The transverse slider 25 is slidably connected to the transverse sliding rod 22, and the transverse sliding block 25 is provided with threaded holes. The thread is connected with the transverse slider 25, there are two transverse sliders 25, one of the transverse sliders 25 is threadedly connected with the transverse screw rod 23, the other transverse slider 25 is slidably connected with the polished rod, and the transverse motor 24 is fixedly connected On the fixing plate 21 , the output shaft of the transverse motor 24 is fixedly connected with the transverse screw rod 23 , the two ends of the longitudinal sliding rod 26 are fixedly connected with the two transverse sliding blocks 25 , and the longitudinal sliding block 29 is slidably connected to the longitudinal sliding block 25 . The rod 26 and the longitudinal sliding block 29 are provided with threaded holes, the longitudinal sliding block 29 is fixedly connected with the vertical frame 2, the two ends of the longitudinal screw rod 27 are installed on the two transverse sliding blocks 25 through the bearing seat, and the longitudinal The screw rod 27 is connected with the longitudinal sliding block 29 through threads, the longitudinal motor 28 is installed on the transverse sliding block 25 , and the output shaft of the longitudinal motor 28 is fixedly connected with the longitudinal screw rod 27 . The horizontal and vertical movement is adopted to allow the cutting part to move arbitrarily on the horizontal plane. The motor-driven screw is used to drive the slider to move. It runs smoothly, has high precision and is easy to control.

As shown in FIG. 1 , the cutting head 8 is composed of a rotating head 9, a mounting frame 10 and a cutting torch head 11. The mounting frame 10 is connected to the rotating head 9, and the cutting torch head 11 is fixed on the in the mounting frame 10.

As shown in FIG. 3 , the rotating head 9 includes a bearing mounting seat 31 , a rotating shaft 32 , a rotating gear 33 , and a rotating motor 34 , the bearing mounting seat 31 is fixed on the top of the beam 3 , and the rotating shaft 32 is mounted on the bearing In the mounting seat 31, the rotating gear 33 is fixed on the upper part of the rotating shaft 32, the rotating motor 34 is fixed on the bearing mounting seat 31 through a bracket, and the output shaft of the rotating motor 34 is meshed with the rotating gear 33 through a gear. The rotation of the rotating shaft 32 is controlled by the rotating motor 34 to control the angle of the cutting head, which is easy to adjust in use. The mounting frame 10 includes a bracket 35, a pin block 36, a fixed head 37 and a swing cylinder 38. The bracket 35 is L-shaped, and the pin block 36 is fixed on the top of the horizontal section of the bracket 35. The middle part of the fixed head 37 is welded on the pin shaft block 36 , one end of the swing cylinder 38 is fixed on the bracket 35 through the pin shaft, and the other end is fixed on the end of the fixed head 37 through the pin shaft. The fixed head 37, that is, the angle of the cutting head, is controlled by the expansion and contraction of the swinging cylinder 38, wherein the bracket 35 is L-shaped, which greatly enlarges the cutting angle.

As shown in FIG. 4 , the fixing head 37 is composed of two semicircular fixing pieces 41, one side of the two semicircular fixing pieces 41 is connected by a pin shaft, and the other side is welded with a fixing ring 42, The fixing ring 42 is fixed by fixing bolts 43 . The fixing piece 41 has a good fixing effect on the cutting head, which greatly improves the cutting precision.

As shown in FIG. 5 , the cross beam 3 is composed of two parts, which are a rear pipe 51 and a front pipe 52 respectively. A telescopic oil cylinder 53 is fixedly connected, and the front end of the telescopic rod of the telescopic oil cylinder 53 is fixedly connected to the front pipe 52 . The telescopic beam 3 increases the scope of processing workpieces and improves the scope of application.

Further, the semicircular fixing piece 41 is made of heat-resistant material. The heat-resistant material greatly increases the working life of the semicircular fixing piece 41 .

Further, the elevating motor 6 , the horizontal motor 24 , the vertical motor 28 , the swinging cylinder 38 , the rotating motor 34 , and the telescopic oil cylinder 53 are controlled by the same controller. The whole of the integrated control makes the operation smooth, easy to control, and coordinated control, which can cut the required workpiece.

Further, the brackets 35 can be replaced with L-shaped brackets of different proportions according to the needs of processing workpieces. L-shaped brackets with different proportions are convenient to change the angle and meet the processing needs of different workpieces.

As shown in FIG. 6 , the cutting torch head 11 is a plasma cutting machine torch head, and the cutting torch head 11 is composed of a torch head 61, an electrode 62, a shunt 63, a contact nozzle 64, and a protective cover 65. The cutting torch head 11 is fixed in the two semicircular fixing pieces 41, the cutting torch head 11 is connected to the plasma cutting machine 67 through the connecting pipe 66, the electrode 62 is installed in the cutting torch head 11, and the shunt 63 is installed in the plasma cutting machine 67. Inside the cutting torch head 11 , the contact tip 64 is installed in the cutting torch head 11 , and the protective cover 65 is fixedly connected to the inner bottom end of the cutting torch head 11 .

Principles and advantages of the present invention: The present invention discloses a mechanical processing device capable of cutting at any angle. When in use, firstly, the cutting torch head 11 of the plasma cutting machine is fixedly installed on the fixed head 37, and the two are fixed by the fixing bolts 43. A semicircular fixed piece 41 clamps the working head of the plasma cutting machine, and by adjusting the beam 3 to a suitable length, the moving support 1 controls the cutting head 8 to move arbitrarily in the horizontal direction, and the lift motor 6 can control the cutting head 8 It moves up and down in the vertical direction, and the rotating motor 34 can control the free selection of the cutting head 8 in the horizontal direction, and through the expansion and contraction of the swinging cylinder 38, the angle between the cutting head 8 and the horizontal plane can be changed. Arbitrary angle; the motor drives the screw to drive the slider to move, which is more stable than the traditional driving method of the oil cylinder cylinder and the motor gear, which greatly improves the processing accuracy; the cutting is completed at one time, which greatly reduces the production cost; one Controlled and easy to use.

The specific working process is as follows: the lifting motor 6 drives the lifting screw 7 to rotate, thereby driving the sliding sleeve 4 to change the position up and down, that is, the cutting head can move up and down in the vertical direction.

The transverse motor 24 drives the transverse screw 23 to rotate, thereby driving the transverse slider 25 to move left and right in the transverse direction of the horizontal plane, that is, the changing action of making the cutting head move left and right in the transverse direction of the horizontal plane;

The longitudinal motor 28 drives the longitudinal screw 26 to rotate, thereby driving the longitudinal slider 29 to move back and forth in the longitudinal direction of the horizontal plane, that is, the changing action of making the cutting head move back and forth in the longitudinal direction of the horizontal plane;

The swinging cylinder 38 pushes the fixed head 37 to rotate around the bracket 35 through its own expansion and contraction, thereby changing the angle of the fixed head 37 on the vertical plane, that is, the changing action of swinging the cutting head on the vertical plane;

The rotating motor 34 drives the rotating shaft of the rotating shaft 32 through the gear and the rotating gear 33, so that the cutting head rotates with the rotating shaft as the axis, that is, the changing action of rotating the cutting head in the vertical direction;

The telescopic oil cylinder 53 can be extended to an appropriate length according to the processing specifications of the workpiece to meet the processing needs of different workpieces;

Through the above four action changes and one adjustment change, the cutting head can be freely moved and the cutting angle can be changed, and the cutting angle has a wide range. This structure is used to solve the problem of limited cutting angle in the prior art, thereby eliminating the secondary or even more The trouble of secondary processing greatly reduces the cost of product workpieces.

The above descriptions are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention shall be included in the protection of the present invention. within the range.

Claims (4)

1. it is a kind of be able to achieve any angle cutting machining equipment, including mobile support saddle (1), vertical stand (2), crossbeam (3), Sliding sleeve (4), mounting plate (5), lifting motor (6), elevating screw (7), cutting head (8), the mobile support saddle (1) are mounted on rack On, the vertical stand (2) is arranged on mobile support saddle (1), and sliding slot is provided on vertical stand (2), and the sliding sleeve (4) is logical It crosses sliding slot to be slidably connected on vertical stand (2), and sliding sleeve (4) offers threaded hole along the vertical direction, the crossbeam (3) is horizontal It is connected to sliding sleeve (4) side, the mounting plate (5) is fixed at the top of vertical stand (2), the elevating screw (7) up and down two End is connected on mounting plate (5) and mobile support saddle (1) by bearing block, and elevating screw (7) passes through screw thread and sliding sleeve (4) Connection, the lifting motor (6) is fixed on mounting plate (5), and lifting motor (6) output shaft and elevating screw (7) are affixed, The cutting head (8) is mounted on the end of crossbeam (3)；

It is characterized by:

The mobile support saddle (1) includes fixed plate (21), horizontal sliding bar (22), cross lead screw (23), cross motor (24), cross To sliding block (25), longitudinal slide bar (26), longitudinal screw mandrel (27), longitudinal motor (28) and longitudinal sliding block (29), the fixed plate It (21) is two, two fixed plates (21) are arranged in parallel, (22) two one group of the horizontal sliding bar, horizontal sliding bar (22) both ends point It is not fixed on fixed plate (21), the transverse slider (25) is slidably connected on horizontal sliding bar (22), and transverse slider (25) threaded hole is provided on, the cross lead screw (23) both ends are mounted on fixed plate (21) by bearing block, and transverse wire Bar (23) is connect by screw thread with transverse slider (25), and the cross motor (24) is fixed on fixed plate (21), and laterally Motor (24) output shaft and cross lead screw (23) are affixed, and longitudinal slide bar (26) both ends and two transverse sliders (25) are affixed, The longitudinal sliding block (29) is slidably connected on longitudinal slide bar (26), and threaded hole is provided on longitudinal sliding block (29), longitudinal sliding Block (29) and vertical stand (2) are affixed, and longitudinal screw mandrel (27) both ends are mounted on two transverse sliders (25) by bearing block, And longitudinal screw mandrel (27) is connected through a screw thread with longitudinal sliding block (29), the longitudinal motor (28) is mounted on transverse slider (25) On, and longitudinal motor (28) output shaft and longitudinal screw mandrel (27) are affixed；The cutting head (8) is by swivel head (9), mounting rack (10) it is connected on swivel head (9) with cutting pipette tips (11) composition, the mounting rack (10), the cutting pipette tips (11) are solid It connects in mounting rack (10)；The swivel head (9) includes bearing mounting base (31), shaft (32), rotation gear (33) and turns Dynamic motor (34), the bearing mounting base (31) are fixed in crossbeam (3) end, and the shaft (32) is mounted on bearing installation In seat (31), the rotation gear (33) is fixed in shaft (32) top, and the rotary electric machine (34) is affixed by bracket On bearing mounting base (31), and the output shaft of rotary electric machine (34) is engaged by gear with rotation gear (33)；The peace Shelving (10) includes bracket (35), pin shaft block (36), fixing head (37) and oscillating cylinder (38), and the bracket (35) is L shape, The pin shaft block (36) is fixed in the end of bracket (35) horizontal segment, is welded on pin shaft block in the middle part of the fixing head (37) (36) on, the oscillating cylinder (38) one end is fixed on bracket (35) by pin shaft, and the other end is fixed in solid by pin shaft Determine the top of head (37)；

The fixing head (37) includes two semicircle fixinig plates (41), and described two semicircle fixinig plate (41) sides pass through Pin shaft connection, the other side are welded with retainer plate (42), pass through retainer plate (42) for two semicircles by fixing bolt (43) Fixinig plate link into an integrated entity, the semicircle fixinig plate (41) is made of heat proof material.

2. a kind of machining equipment for being able to achieve any angle cutting according to claim 1, it is characterised in that: described Crossbeam (3) be divided into after manage (51) and front tube (52) two parts, the front tube (52) be slidably connected at by sliding slot after pipe (51) Inside, the rear pipe (51) is internal to be connected with a telescopic oil cylinder (53), and the telescopic rod front end of the telescopic oil cylinder (53) is solid It connects on front tube (52).

3. a kind of machining equipment for being able to achieve any angle cutting according to claim 2, it is characterised in that: described Lifting motor (6), cross motor (24), longitudinal motor (28), oscillating cylinder (38), rotary electric machine (34), telescopic oil cylinder (53) it is controlled by same controller.

4. a kind of machining equipment for being able to achieve any angle cutting according to claim 3, it is characterised in that: described Cutting pipette tips (11) be plasma cutter gun head, cutting pipette tips (11) include pipette tips (61), electrode (62), current divider (63), ignition tip (64) and protective cover (65), the cutting pipette tips (11) are fixed in two semicircle fixinig plates (41), cut Burning torch head (11) is connect by connecting pipe (66) with plasma cutting machine (67), and the electrode (62) is mounted on cutting pipette tips (11) in, the current divider (63) is mounted in cutting pipette tips (11), and the ignition tip (64) is mounted on cutting pipette tips (11) in, the protective cover (65) is fixed in cutting pipette tips (11) bottom end.