CN112140628A - Cantilever type retooling arm - Google Patents

Abstract

The invention relates to a cantilever type die changing arm, belonging to the technical field of mechanical equipment; a cantilever type die changing arm comprises a mounting positioning plate, a driving assembly arranged on the mounting positioning plate, a guide assembly in transmission connection with the driving assembly, and a swing arm supporting mechanism arranged in the guide assembly in a matching manner; the swing arm supporting mechanism is hinged with a swing arm mechanism, and the swing arm mechanism is hinged with a mould connecting mechanism; a clamp mechanism for clamping the mold to be moved is fixedly arranged on the mold connecting mechanism; the fixture mechanism comprises a fixed frame fixedly arranged on the die connecting mechanism, a fixed arm and a movable arm which is opposite to the fixed arm and arranged at the tail end of the fixed frame are arranged, and the movable arm is connected inside the fixed frame in a sliding mode.

Description

Cantilever type retooling arm

Technical Field

The invention relates to the technical field of mechanical joint arms, in particular to a cantilever type die changing arm.

Background

With the development of large-scale press machines in various, high-speed, automatic and flexible directions, how to quickly replace the die becomes a bottleneck restricting efficient production, and particularly for large-tonnage press machines, the difficulty of quickly replacing the die is higher and the time is longer. In the mode of retooling of present domestic press, mainly rely on the manpower to directly change small-size press, then must wholly shift out the press with last mould and lower mould to large-scale press, borrow other instruments to carry out the retooling again, its retooling is inefficient, and when large-scale frock mould dismouting was carried in addition, workman's intensity of labour is also great.

The Chinese invention with the grant bulletin number of CN104108198B discloses a telescopic lifting die change arm, which comprises a fixed seat connected with a machine body and a die change arm connected with the fixed seat, wherein one end of the die change arm is provided with an arm supporting seat, the tail end of the die change arm is provided with a hanging mechanism, two rows of linear sliding rails which are parallel to each other and are in the vertical direction are arranged between the arm supporting seat and the fixed seat, the fixed seat is also vertically provided with a hydraulic cylinder, and the end part of a telescopic rod of the hydraulic cylinder is fixedly connected with the arm supporting seat and used for driving the die change arm to move up and down along the linear sliding; the mould changing arm comprises two or more than two joint arms which can be folded and rotated, and the arm supporting seat is connected with the first joint arm and each joint arm through a rotating mechanism; the telescopic lifting die changing arm can realize efficient and rapid die changing and greatly reduce the labor intensity of die changing work of operators.

The cantilever type mold changing arm has the following defects: this mechanism of hanging only adopts wire rope to connect the couple and colludes the mould of treating the change, and at the in-process that promotes, thereby the mould of heavy weight can take place to rock and lead to several knuckle arms to receive very big load power and take place to deform or even damage, has great potential safety hazard.

Disclosure of Invention

Aiming at the defects in the prior art, the invention aims to provide a cantilever type die changing arm, which adopts a servo motor to drive a screw rod through a worm and gear speed reducer.

The above functions of the invention are realized by the following technical scheme:

a cantilever type die changing arm comprises a mounting positioning plate, a driving assembly arranged on the mounting positioning plate, a guide assembly in transmission connection with the driving assembly, and a swing arm supporting mechanism arranged in the guide assembly in a matching manner; the swing arm supporting mechanism is hinged with a swing arm mechanism, and the swing arm mechanism is hinged with a mould connecting mechanism; a clamp mechanism for clamping the mold to be moved is fixedly arranged on the mold connecting mechanism; the fixture mechanism comprises a fixed frame fixedly arranged on the die connecting mechanism, a fixed arm and a movable arm which is opposite to the fixed arm and arranged at the tail end of the fixed frame are arranged, and the movable arm is connected inside the fixed frame in a sliding mode.

Through adopting above-mentioned technical scheme, to install the locating plate through a plurality of bolt fastening in the frame, carry out the bolt fastening through mould coupling mechanism with the mould of treating the removal, under the effect of direction subassembly, mould on mould coupling mechanism reciprocates thereupon and adjusts for actual need's position, but also just it waves to sway the arm mechanism and can swing the adjustment around on the arm supporting mechanism, it also can wave back and forth adjustment before with the articulated mould coupling mechanism of arm mechanism, according to actual need's position and adjustment around, the operation of moving on the mould has been replaced the manual work, make work efficiency and accuracy improve greatly, on the other hand can install on the press stand by monolithic, need not carry out big transformation to equipment, it is convenient to install, it is convenient to maintain.

The present invention in a preferred example may be further configured to: the driving assembly comprises a servo motor, a worm and gear speed reducer is connected to the driving end of the servo motor, a lead screw is connected to the output end of the worm and gear speed reducer, and the swing arm supporting mechanism is in threaded connection with the lead screw through a threaded sleeve.

Through adopting above-mentioned technical scheme, servo motor increases torsion through worm gear speed reducer's cooperation down, can drive the swing arm supporting mechanism on the lead screw and move in the lift, realizes that the mould does and reciprocates and cooperate the actual operation.

The present invention in a preferred example may be further configured to: and the mounting positioning plate is also provided with an upper limit inductive switch and a lower limit inductive switch.

Through adopting above-mentioned technical scheme, can protect servo motor through last spacing inductive switch and lower spacing inductive switch's setting, avoid servo motor to transship.

The present invention in a preferred example may be further configured to: the guide assembly comprises a left guide rod and a right guide rod; and the left guide rod and the right guide rod are respectively provided with a left guide connecting sleeve and a right guide connecting sleeve which are used for connecting the swing arm supporting mechanism.

The left guide rod and the right guide rod play a guiding role in moving up and down, and lateral force received by the screw rod is reduced simultaneously, so that the moving up and down position is accurate and in place, the service life of the screw rod is prolonged, the left guide rod and the right guide rod can slide up and down particularly through the left guide connecting sleeve and the right guide connecting sleeve, and lubricating oil can be injected into the left guide connecting sleeve and the right guide connecting sleeve to be in better sliding connection with the left guide rod and the right guide rod.

The present invention in a preferred example may be further configured to: the swing arm supporting mechanism comprises an upper supporting plate, a middle supporting plate and a lower supporting plate which are sequentially sleeved on the left guide connecting sleeve and the right guide connecting sleeve from top to bottom;

the middle supporting plate is in threaded connection with the screw rod through a threaded sleeve and can ascend/descend above the screw rod.

By adopting the technical scheme, the upper supporting plate, the middle supporting plate and the lower supporting plate which are sleeved on the left guide connecting sleeve and the right guide connecting sleeve form the swing arm supporting mechanism, the swing arm supporting mechanism is in threaded connection with the screw rod through the threaded sleeve, and the lifting operation is performed under the condition that the screw rod rotates according to the conversion of the positive rotation and the negative rotation of the servo motor.

The present invention in a preferred example may be further configured to: the swing arm mechanism comprises a swing arm and a transverse pushing handle arranged on the side surface of the swing arm; the swing arm is arranged between the upper support plate and the lower support plate and is in pin joint with the upper support plate through a swing arm pin shaft, an upper damping sleeve for increasing damping force when the swing arm pin shaft and the upper support plate move is arranged at the matching position of the swing arm pin shaft and the upper support plate, and a lower damping sleeve for increasing damping force when the swing arm pin shaft and the lower support plate move is arranged at the matching position of the swing arm pin shaft and the lower support plate; the swing arm is provided with a first protective sleeve covering the position of the pin shaft of the swing arm and a first protective plate covering the position of the main body of the swing arm.

Through adopting above-mentioned technical scheme, swing arm mechanism passes through swing arm round pin axle and articulates the setting between last backup pad, bottom suspension fagging, and it can be through violently pushing away the handle and doing the front and back promotion operation to it, and the operating mode of man-machine cooperation has replaced pure artificial operating mode for the efficiency of transport can improve.

The present invention in a preferred example may be further configured to: the device also comprises a mounting mechanism for mounting the guide component; the mounting mechanism comprises an upper transverse supporting plate and a lower transverse supporting plate which are distributed at the upper end and the lower end of the mounting positioning plate, and a left longitudinal mounting plate and a right longitudinal mounting plate which are respectively arranged at the two ends of the upper transverse supporting plate.

Through adopting above-mentioned technical scheme, should go up horizontal backup pad, left longitudinal installation board, right longitudinal installation board down all fix on the installation locating plate through a plurality of bolts and four cooperation forms a rectangular installation mechanism, owing to be the rectangle make installation mechanism more stable and solid.

The present invention in a preferred example may be further configured to: the die connecting mechanism comprises a connecting arm; one end of the connecting arm is in pin joint with the tail end of the swing arm through a mould connecting pin shaft, and the other end of the connecting arm is fixedly provided with a mould fixing plate; the main body of the connecting pin shaft of the die is sleeved with a main damping sleeve, and the upper and lower inner walls of the connecting arm are abutted to the upper and lower damping sleeves; wherein, the main protection board is arranged at the main body position of the connecting arm.

Through adopting above-mentioned technical scheme, when needing to move the mould, adopt bolt fixed connection with mould fixed plate and mould to guarantee that the contact is stable, then use mould connecting pin axle to make front and back adjustment as the fulcrum through the swing arm with mould fixed plate fixed connection, especially, the cooperation has main damping cover on the mould connecting pin axle, provides certain damping force and prevents that mould back-and-forth movement position is too big to lead to damaging mould coupling mechanism.

The present invention in a preferred example may be further configured to: the lead screw is equipped with the external screw thread outward and its end sets up in horizontal backup pad under through the bearing cooperation, the lead screw has cup jointed lead screw protective sheath and lead screw protective sheath down, go up lead screw protective sheath upper end butt and in last horizontal backup pad inboard, its lower extreme butt is in the outside of horizontal backup pad down, lead screw protective sheath upper end butt is in the outside of backup pad down, its lower extreme butt is in the outside of horizontal backup pad down.

Through adopting above-mentioned technical scheme, consider that the lead screw of outband screw thread needs to pass through thread bush looks spiro union to swing arm supporting mechanism who realizes being connected with the thread bush with the pivoted mode is done the lift and moves, consequently, prevents that debris such as dust in the environment from being infected with on the lead screw of taking the external screw thread, installs respectively at its upper and lower both ends and is used for isolated outside last lead screw protective sheath and lower lead screw protective sheath of using, makes the life of lead screw and thread bush improve.

The present invention in a preferred example may be further configured to: the left guide connecting sleeve and the right guide connecting sleeve are respectively provided with a left oil filling hole and a right oil filling hole.

Through adopting above-mentioned technical scheme, provide the oil storage through left oil filler point, right oil filler point to left direction adapter sleeve, right direction adapter sleeve for left direction adapter sleeve, right direction adapter sleeve are inside to remain lubricated all the time, make can with left guide bar and the better slip of right guide bar, make the lift operation more smooth.

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

1. the mould passes through fixture mechanism and carries out the centre gripping, and stability is high, can adjust its position through violently pushing away the handle in the promotion stage, has good operability.

2. The lead screw can be protected from being exposed outside through the upper lead screw protective sleeve and the lower lead screw protective sleeve so as to prevent the lead screw from being contaminated by external dust or water vapor, and the service life of the driving assembly is greatly prolonged.

Drawings

FIG. 1 is a schematic axial view of the present invention;

FIG. 2 is a schematic perspective view of the present invention;

FIG. 3 is a schematic view of the assembly structure of the mounting plate, the driving assembly and the guiding assembly of the present invention;

FIG. 4 is a schematic front view of the present invention;

FIG. 5 is a schematic perspective view of the clamping mechanism of the present invention;

fig. 6 is a schematic bottom view of the clamp mechanism of the present invention.

Reference numerals:

1. installing a positioning plate;

2. a drive assembly; 21. a servo motor 22, a worm gear speed reducer 23, a screw rod 24, an upper screw rod protective sleeve and a lower screw rod protective sleeve,

3. a guide assembly; 31. a left guide rod 32, a right guide rod 33, a left guide connecting sleeve 34, a right guide connecting sleeve,

4. a swing arm support mechanism; 41. an upper supporting plate 42, a middle supporting plate 43, a lower supporting plate 44 and a thread sleeve,

5. a swing arm mechanism; 51. a swing arm 52, a transverse pushing handle 53, a swing arm pin shaft 54, an upper damping sleeve 55, a lower damping sleeve 56, a first protective sleeve 57, a first protective plate,

6. a mold connecting mechanism; 61. a connecting arm 62, a connecting pin shaft 63, a mould fixing plate 64, a main upper damping sleeve 65, a main lower damping sleeve 66, a main protective sleeve 67, a main protective plate 67,

7. an installation mechanism; 71. an upper transverse supporting plate 72, a lower transverse supporting plate 73, a left longitudinal mounting plate,

8. a clamp mechanism; 81. a fixed mount 811, a slide rail; 82. a fixed arm 83, a movable arm 84, a locking rod 85 and a locking block,

91. an upper limit inductive switch and a lower limit inductive switch.

Detailed Description

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

Referring to fig. 1, a cantilever type mold changing arm comprises an installation positioning plate 1 which can be installed and fixed on a rack through a plurality of bolts, a guide assembly 3 which is longitudinally installed on an installation mechanism 7, a driving assembly 2 which drives the guide assembly 3 to operate, a swing arm supporting mechanism 4 which can move up and down in the guide assembly 3, a swing arm mechanism 5 which can rotate on the swing arm supporting mechanism 4, a mold connecting mechanism 6 which can rotate on the swing arm mechanism 5, and a clamp mechanism 8 which is fixedly arranged on the mold connecting mechanism 6 and used for hoisting a mold. Wherein, the swing arm mechanism 5 and the swing arm mechanism 5 can be mutually hinged together and can be combined in a plurality of ways according to requirements.

Referring to fig. 1, the mounting and positioning plate 1 is rectangular, and the upper end of the mounting and positioning plate is provided with a plurality of screw holes (not shown) penetrating through the mounting and positioning plate, and the screw holes (not shown) can be used for fixing the mounting and positioning plate 1 on a rack by a plurality of bolts.

Referring to fig. 1 and 2, the driving assembly 2 includes a servo motor 21 fixedly disposed on the mounting positioning plate 1, a worm and gear speed reducer 22 coaxially connected to the servo motor 21, and a lead screw 23 cooperatively connected to the worm and gear speed reducer 22, wherein the servo motor 21 and the worm and gear speed reducer 22 are disposed on a same horizontal line, the lead screw 23 is vertically disposed on the worm and gear speed reducer 22, and a thread bushing 44 is disposed at an upper end of the lead screw 23, the swing arm supporting mechanism 4 on the thread bushing 44 moves up and down under rotation of the lead screw 23, and the lead screw 23 is sleeved with an upper lead screw protective sleeve 24 and a lower lead screw protective sleeve 25 for preventing dust from entering.

Referring to fig. 3 and 4, the mounting mechanism 7 is composed of an upper transverse support plate 71, a lower transverse support plate 72, a left longitudinal mounting plate 73, and a right longitudinal mounting plate 74 and forms a rectangular mounting mechanism, one end of the screw 23 passes through the upper transverse support plate 71 to be matched and connected with the worm gear reducer 22 at the upper end of the upper transverse support plate 71, the other end is matched and arranged in the lower transverse support plate 72 through a bearing, so that the screw 23 can rotate in the rectangular mounting mechanism under the driving of the worm gear reducer 22,

referring to fig. 3 and 4, the guide assemblies 3 are arranged on two sides inside the rectangular mounting mechanism 7, the left guide rod 31 and the left guide connecting sleeve 33 sleeved on the left guide rod 31 are in one group and are arranged on the left side inside the mounting mechanism 7, and the right guide rod 32 and the right guide connecting sleeve 34 sleeved on the right guide rod 32 are in one group and are arranged on the right side inside the mounting mechanism 7, and the two groups are parallel to each other. The left oil filling hole 331 capable of being filled with grease from the outside is formed in the left guide connecting sleeve 33, the left guide connecting sleeve 33 is filled with grease, the left guide rod 31 can better perform sliding operation, the right oil filling hole 341 capable of being filled with grease from the outside is formed in the right guide connecting sleeve 34, and the right guide connecting sleeve 34 is filled with grease, and the right guide rod 32 can better perform sliding operation.

Referring to fig. 1 and 2, the swing arm supporting mechanism 4 includes an upper supporting plate 41 simultaneously sleeved on the upper ends of the left and right guide connecting sleeves 33, 34, and a lower supporting plate 43 simultaneously sleeved on the lower ends of the left and right guide connecting sleeves 33, 34, and a middle supporting plate 42 simultaneously sleeved on the middle portions of the left and right guide connecting sleeves 33, 34, and the middle supporting plate 42 is further sleeved on the thread bush 44, a cover plate 45 for preventing external dust from entering the swing arm supporting mechanism 4 is covered between the upper supporting plate 41 and the lower supporting plate 43, a first channel 451 and a second channel (not marked in the figure) are further arranged on the cover plate 45 in a penetrating manner, and the number of the first channel 451 and the number of the right oil holes 341 are larger than that of the left oil hole 331, and the number of the second channel 341 are larger than that of the.

Referring to fig. 1-4, the swing arm mechanism 5 includes a swing arm 51 hinged between the upper support plate 41 and the lower support plate 43 through a swing arm pin 53, and a first protection plate 57 covering the swing arm 51, wherein an upper damping sleeve 54 and a lower damping sleeve 55 are disposed at the upper and lower matching positions of the swing arm pin 53 and the swing arm 51. The upper damping sleeve 54 and the lower damping sleeve 55 are respectively provided with an upper oil injection hole (not marked in the figure) and a lower oil injection hole (not marked in the figure), the upper oil injection hole (not marked in the figure) and the lower oil injection hole (not marked in the figure) can be filled with oil from the outside at regular time to enable the inside to be in a lubricating environment, the outside of the upper oil injection hole and the lower oil injection hole is also provided with a first protective sleeve 56 for preventing external dust from entering the inside, and when the swing arm 51 needs to rotate, the swing arm only needs to push the transverse push handle 52 to. An upper limit induction switch 91 and a lower limit induction switch 92 are further arranged on the installation positioning plate 1, and the positions of the upper supporting plate 41 and the lower supporting plate 43 are judged through the inductors, so that the servo motor is prevented from rotating and overloading.

Referring to fig. 2, the mold connecting mechanism 6 includes a connecting arm 61 hinged to the swing arm 51 through a connecting pin 63, and a main protection plate 65 covering the connecting arm 61, wherein a main damping sleeve 64 is disposed at the upper and lower matching position of the connecting pin 62 and the connecting arm 61. The main damping sleeve (not marked in the figure) is also provided with a main oil hole (not marked in the figure) respectively, the main oil hole (not marked in the figure) can be filled with oil from the outside at regular time to enable the inside of the main oil hole to be in a lubricating environment, and the outside of the main oil hole is also provided with a main protective sleeve 66 for preventing external dust from entering the inside.

Referring to fig. 5 and 6, the clamping mechanism 8 includes a fixing frame 81 fixedly disposed on the mold connecting mechanism 6, a fixing arm 82 and a movable arm 83 disposed opposite to the fixing arm 82 are disposed at the end of the fixing frame 81, the movable arm 83 is slidably connected inside the fixing frame 81, the fixing frame 81 is provided with a sliding rail 811 for allowing the movable arm 83 to slide, a locking rod 84 passing through the movable arm 83 is disposed on the movable arm 83, and the locking rod 84 is locked by lifting a locking block 85 to the sliding rail 811.

The working principle is as follows: the fixed arm 82 of the clamp mechanism 8 is clamped at one end of a mold to be lifted, the movable arm 83 slides to the other end of the mold to be lifted on the sliding rail 811, the movable arm 83 is locked at a specified position through the locking rod 84, at the moment, the mold to be lifted is firmly fixed, the driving assembly 2 works to lift the swing arm supporting mechanism 4 through the screw rod 23, then, the swing arm mechanism 5 hinged to the swing arm supporting mechanism 4 is naturally lifted upwards together with the mold connecting mechanism 6 and the clamp mechanism 8, after the mold to be lifted is lifted to a certain position, the mold to be lifted needs to be moved transversely, the swing arm mechanism 5 can drive the mold connecting mechanism 6 to move transversely, and the mold connecting mechanism 6 can drive the clamp mechanism 8 to move transversely.

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

Claims (10)

1. A cantilever type die changing arm comprises a mounting positioning plate (1), a driving assembly (2) arranged on the mounting positioning plate (1), a guide assembly (3) in transmission connection with the driving assembly (2), and a swing arm supporting mechanism (4) arranged in the guide assembly (3) in a matching manner; the method is characterized in that: the swing arm supporting mechanism (4) is hinged with a swing arm mechanism (5), and the swing arm mechanism (5) is hinged with a mould connecting mechanism (6); a clamp mechanism (8) for clamping a mold to be moved is fixedly arranged on the mold connecting mechanism (6); the fixture mechanism (8) comprises a fixed frame (81) fixedly arranged on the die connecting mechanism (6), a fixed arm (82) and a movable arm (83) which is opposite to the fixed arm (82) and is arranged at the tail end of the fixed frame (81), and the movable arm (83) is slidably connected inside the fixed frame (81).

2. The cantilevered mode-changing arm of claim 1, wherein: the driving assembly (2) comprises a worm gear speed reducer (22) connected to the driving end of the servo motor (21), the output end of the worm gear speed reducer (22) is connected with a screw rod (23), and the swing arm supporting mechanism (4) is in threaded connection with the screw rod (23) through a threaded sleeve (44).

3. The cantilevered mode-changing arm of claim 2, wherein: an upper limit induction switch (91) and a lower limit induction switch (92) are further arranged on the mounting positioning plate.

4. The cantilevered mold changing arm of claim 3, wherein: the guide assembly (3) comprises a left guide rod (31) and a right guide rod (32); and a left guide connecting sleeve (33) and a right guide connecting sleeve (34) which are used for connecting the swing arm supporting mechanism (4) are respectively arranged on the left guide rod (31) and the right guide rod (32).

5. The cantilevered mode-changing arm of claim 4, wherein: the swing arm supporting mechanism (4) comprises an upper supporting plate (41), a middle supporting plate (42) and a lower supporting plate (43) which are sequentially sleeved on the left guide connecting sleeve (33) and the right guide connecting sleeve (34) from top to bottom;

the middle support plate (42) is connected with the screw rod (23) through a threaded sleeve (44) and can ascend/descend above the screw rod (23).

6. The cantilevered mode-changing arm of claim 5, wherein: the swing arm mechanism (5) comprises a swing arm (51) and a transverse pushing handle (52) arranged on the side surface of the swing arm (51); the swing arm (51) is arranged between the upper supporting plate (41) and the lower supporting plate (43) and is in pin joint through a swing arm pin shaft (53), an upper damping sleeve (54) used for increasing damping force when the swing arm pin shaft (53) and the upper supporting plate (41) move is arranged at the matching position of the swing arm pin shaft (53) and the lower supporting plate (43), and a lower damping sleeve (55) used for increasing damping force when the swing arm pin shaft (53) and the lower supporting plate (43) move is arranged at the matching position of the swing arm pin shaft (53); the swing arm (51) is provided with a first protective sleeve (56) covering the position of the swing arm pin shaft (53) and a first protective plate (57) covering the main body of the swing arm pin shaft.

7. The cantilevered mode-changing arm of claim 5, wherein: the device also comprises a mounting mechanism (7) for mounting the guide component (3); the mounting mechanism (7) comprises an upper transverse support plate (71) and a lower transverse support plate (72) which are distributed at the upper end and the lower end of the mounting positioning plate (1), and a left longitudinal mounting plate (73) and a right longitudinal mounting plate (74) which are respectively arranged at the two ends of the upper transverse support plate (71).

8. The cantilevered mode-changing arm of claim 5, wherein: the mould connecting mechanism (6) comprises a connecting arm (61); one end of the connecting arm (61) is connected to the tail end of the swing arm (51) in a pin mode through a die connecting pin shaft (62), and the other end of the connecting arm is fixedly provided with a die fixing plate (63); a main damping sleeve (64) is sleeved in the main body of the die connecting pin shaft (62), and the main damping sleeve (64) is abutted against the upper inner wall and the lower inner wall of the connecting arm (61) up and down; wherein, a main protection plate (65) is arranged at the main body position of the connecting arm (61).

9. The cantilevered mode-changing arm of claim 7, wherein: the lead screw (23) is equipped with external screw thread (231) outward and its end sets up in horizontal backup pad (72) down through the bearing cooperation, lead screw (23) have been cup jointed lead screw protective sheath (24) and lead screw protective sheath (25) down, go up lead screw protective sheath (24) upper end butt and in last horizontal backup pad (71) inboard, the outside of horizontal backup pad (72) under its lower extreme butt, the outside of backup pad (43) is in down in lead screw protective sheath (25) upper end butt, the outside of horizontal backup pad (72) under its lower extreme butt.

10. The cantilevered mode-changing arm of claim 4, wherein: the left guide connecting sleeve (33) and the right guide connecting sleeve (34) are respectively provided with a left oil filling hole (331) and a right oil filling hole (341).

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