CN211857326U

CN211857326U - Electric hand crank

Info

Publication number: CN211857326U
Application number: CN202020397943.3U
Authority: CN
Inventors: 边金城; 丁林锋
Original assignee: Lishi Shanghai Sunshade Technology Co ltd
Current assignee: Lishi Shanghai Sunshade Technology Co ltd
Priority date: 2020-03-25
Filing date: 2020-03-25
Publication date: 2020-11-03
Anticipated expiration: 2030-03-25

Abstract

The utility model provides an electronic crank, including crank body, movable mounting at the shell of crank body middle part outside symmetry, the crank body includes crank hook, thick pipe, the internally mounted of shell has electric drive, electric drive includes movable mounting's motor, drive mechanism, electronic module, drive mechanism includes the first bevel gear of the surface of the inboard thick pipe of shell, the second bevel gear of motor output shaft tip, electronic module includes battery, card at the inboard power control circuit board and the total circuit board of shell, electric drive still includes positioning mechanism. An electronic crank, can satisfy different operating condition's demand, it is more laborsaving, and work efficiency is higher, can avoid the work of crank hook when not using, use more safely, can change the length of crank, be applicable to different job scene.

Description

Electric hand crank

Technical Field

The utility model relates to a crank technical field, in particular to electronic crank.

Background

The hand crank is mostly divided into a foldable structure and an integral structure, the foldable structure comprises a long rod, two short rods and two rotating shafts, the long rod can be pulled into a straight rod, the hand crank can be folded into a hand crank, and the hand crank is integrally formed by the long rod and the two rotating shafts.

The existing hand crank is controlled by hands when in use, is labor-consuming, low in working efficiency and quite inconvenient to use, and the length of the hand crank cannot be adjusted.

SUMMERY OF THE UTILITY MODEL

An object of the utility model is to provide an electronic crank can satisfy different operating condition's demand, and is more laborsaving, and work efficiency is higher, can avoid the work of crank hook when not using, uses more safely, can change the length of crank, is applicable to different work scenes.

The embodiment of the utility model is realized like this:

the embodiment of the utility model provides an electronic crank, including crank body, movable mounting at the shell of crank body middle part outside symmetry, the crank body includes crank hook, thick pipe, the internally mounted of shell has electric drive, electric drive includes movable mounting's motor, drive mechanism, electronic module, drive mechanism includes the first bevel gear of the surface of the inboard thick pipe of shell, the second bevel gear of motor output shaft tip, electronic module includes battery, card at the inboard power control circuit board and the total circuit board of shell, electric drive still includes positioning mechanism, positioning mechanism includes the first motor locking piece in the outside of motor, runs through the motor output shaft the motor moving member at second motor locking piece, first motor locking piece top.

Optionally, the crank body still includes tubule, well pipe, the lower extreme of hand hook is connected with the upper end of tubule, well pipe is connected in the lower part outside of tubule, well pipe is located the upper portion inboard of thick pipe, be provided with first adjustment mechanism between tubule, the well pipe, first adjustment mechanism includes locking cover, internal thread locking rotating member, the locking cover is the opening, the locking cover is in the outside of tubule, and the upside of locking cover is circular downside and twelve-angle flower type, locking cover bottom and well pipe internal surface shape looks adaptation, the inside tangent plane of internal thread locking rotating member is trapezoidal, the internal surface of internal thread locking rotating member and the surface connection of locking cover, and the internal surface of internal thread locking rotating member lower part and well pipe upper portion surface pass through threaded connection, the inboard of well pipe in the bottom of tubule is provided with tubule hexagonal mounting, and the inner side of the thick pipe at the bottom of the middle pipe is provided with a middle pipe hexagonal fixing part, and a second adjusting mechanism is arranged between the thick pipe and the middle pipe.

Through adopting above-mentioned technical scheme, can change the tubule through first adjustment mechanism and go deep into the length in well pipe to change crank length, can die the bottom lock of tubule through tubule hexagonal mounting, avoid the tubule to rotate independently in well intraduct, and can die the bottom lock of well pipe through well pipe hexagonal mounting, avoid well pipe to rotate independently in thick intraduct, fixed more is firm, and transmission effect is better.

Optionally, first bevel gear is fixed in the outside at the thick pipe, be provided with two thick pipe axis of rotation between thick pipe and the shell, the thick pipe passes through thick pipe axis of rotation and shell swing joint, first bevel gear meshes with the second bevel gear mutually, the output shaft fixed connection of second bevel gear and motor, first motor locking piece passes through screwed connection with the second motor locking piece, and the motor moving member passes through screw and first motor locking piece fixed connection, the inside card of the afterbody shell of motor moving member has adjust knob, adjust knob passes through threaded connection with the motor moving member.

By adopting the technical scheme, the motor can drive the thick pipe to rotate by matching the first bevel gear with the second bevel gear.

Optionally, a charging interface is installed on one side, close to the thick pipe, of the upper end of the shell, the charging interface is connected with the main circuit board through a wire, the power supply control circuit board is clamped on the inserting position of the shell, and the surface of the power supply control circuit board is embedded on the inner wall of the shell and is sleeved with the power switch.

Through adopting above-mentioned technical scheme, can charge the battery through the interface that charges.

Optionally, the power control circuit board is connected with the main circuit board through a wire, the inner side of the shell is provided with a jog key, the inner side of the jog key on the surface of the main circuit board is provided with a button, the button is connected with the main circuit board through a wire, the jog key is sleeved on the surface of the button, the jog key is fixed on a screw point convex cylinder of the shell through a screw, and the two groups of shells are fixed through screws.

Through adopting above-mentioned technical scheme, can the starter motor through the inching button.

Optionally, a steering power supply is arranged on the surface of the main circuit board, a steering switch is mounted on the outer side of the steering power supply, a battery frame is arranged between the battery and the shell, and the anode and the cathode of the battery frame are electrically connected with the main circuit board.

By adopting the technical scheme, the steering power supply can be touched by shifting the steering switch, so that the motor rotates reversely.

Optionally, the lower end of the hand crank hook is fixedly connected with the upper end of the thin tube, and the thin tube is movably connected with the middle tube through the first adjusting mechanism.

Optionally, the middle pipe is movably connected with the thick pipe through a second adjusting mechanism, and the thin pipe, the middle pipe and the thick pipe are all made of aluminum materials.

Through adopting above-mentioned technical scheme, can adjust the interior length of pipe in the thick pipe through second adjustment mechanism to change the length of crank.

The utility model discloses beneficial effect includes: the embodiment of the utility model provides an electric crank, start through long press switch, press the inching button after starting up and make the motor work, can drive the second bevel gear rotation through the motor, and second bevel gear passes through the gear interlock with first bevel gear, and then make first bevel gear drive the thick pipe and rotate, can make the crank hook rotate through the thick pipe, thereby make the crank be in operating condition, connect through the thick pipe pivot between thick pipe and the shell, thick pipe is more stable when rotating, can make thick pipe reverse rotation when stirring the steering switch, can satisfy the demand of different operating condition, it is more laborsaving, and work efficiency is higher, can drive the motor moving member to move through the rotation adjusting knob, and the motor moving member passes through first motor locking piece, second motor locking piece is connected with the motor, and then can make the motor move, thereby drive the second bevel gear to move and separate with first bevel gear, avoid touching switch and making hand crank hook work when not using, it is safer to use, in addition, it is intraductal to overlap the locking cover in the outside of tubule and insert the well, lock the outside of rotating member cover at the locking cover with the internal thread, the outside at well pipe is twisted to the bottom that makes the internal thread lock rotating member, because the internal thread locks the outside that the internal surface slope of rotating member can make the locking cover lock die in the tubule, and then make the tubule, well union coupling, can adjust the tubule, height between the well pipe, height between the thick pipe can be adjusted to the same reason, be applicable to different work scenes, the effect of using is better for traditional mode.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings that are required to be used in the embodiments will be briefly described below, it should be understood that the following drawings only illustrate some embodiments of the present invention, and therefore should not be considered as limiting the scope, and for those skilled in the art, other related drawings can be obtained according to the drawings without inventive efforts.

Fig. 1 is a schematic view of the overall structure of an electric crank handle of the present invention;

fig. 2 is a schematic structural view of a crank body of the electric crank of the present invention;

fig. 3 is a schematic structural view of an electric driving device of an electric crank handle of the present invention;

fig. 4 is a partial structure schematic diagram of an electric driving device of an electric crank handle of the present invention;

fig. 5 is a cutting schematic view of the middle tube and the thin tube hexagonal fixing piece of the manual and electric integrated crank of the utility model;

fig. 6 is a schematic view of the cutting structure of the thin tube, the middle tube and the thin tube hexagonal fixing part of the manual and electric integrated crank of the present invention.

Icon: 1. a crank body; 11. a hand crank hook; 12. a thin tube; 13. a middle tube; 14. a first adjustment mechanism; 141. a locking sleeve; 142. an internal thread locking swivel; 15. a thick pipe; 16. a second adjustment mechanism; 17. a thin tube hexagonal fixing piece; 18. a middle tube hexagonal fixing piece; 2. a housing; 3. a thick tube rotating shaft; 4. an electric drive; 41. a motor; 42. a transmission mechanism; 421. a first bevel gear; 422. a second bevel gear; 43. a positioning mechanism; 431. a first motor lock; 432. a second motor lock; 433. a motor moving member; 434. adjusting a knob; 44. an electromotive module; 441. a power supply control circuit board; 442. a power switch; 443. a steering switch; 444. a main circuit board; 445. clicking a key; 446. a battery holder; 447. a battery; 448. and a charging interface.

Detailed Description

In order to make the objects, technical solutions and advantages of the embodiments of the present invention clearer, the drawings in the embodiments of the present invention are combined below to clearly and completely describe the technical solutions in the embodiments of the present invention. Thus, the following detailed description of the embodiments of the present invention, presented in the accompanying drawings, is not intended to limit the scope of the invention, as claimed, but is merely representative of selected embodiments of the invention. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "vertical", "horizontal", "inner", "outer", and the like indicate the position or positional relationship based on the position or positional relationship shown in the drawings, or the position or positional relationship which is usually placed when the product of the present invention is used, and are only for convenience of description and simplification of the description, but do not indicate or imply that the device or element to which the term refers must have a specific orientation, be constructed and operated in a specific orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," "third," and the like are used solely to distinguish one from another and are not to be construed as indicating or implying relative importance.

Furthermore, the terms "horizontal", "vertical" and the like do not imply that the components are required to be absolutely horizontal or pendant, but rather may be slightly inclined. For example, "horizontal" merely means that the direction is more horizontal than "vertical" and does not mean that the structure must be perfectly horizontal, but may be slightly inclined.

In the description of the present invention, it should also be noted that, unless otherwise explicitly specified or limited, the terms "disposed," "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meaning of the above terms in the present invention can be understood in specific cases to those skilled in the art.

The embodiment of the utility model provides an electric crank, as shown in fig. 1, including crank body 1, the shell 2 of movable mounting outside the middle part of crank body 1 symmetry, crank body 1 includes crank hook 11, thick pipe 15, the internally mounted of shell 2 has electric drive device 4, electric drive device 4 includes movable mounting's motor 41, drive mechanism 42, electronic module 44, drive mechanism 42 includes the first bevel gear 421 of the surface of the inboard thick pipe 15 of shell 2, the second bevel gear 422 of motor 41 output shaft tip, electronic module 44 includes battery 447, the power control circuit board 441 and the total circuit board 444 of card in the inboard of shell 2, electric drive device 4 still includes positioning mechanism 43, the positioning mechanism 43 includes a first motor locking member 431 on the outer side of the motor 41, a second motor locking member 432 penetrating the output shaft of the motor 41, and a motor moving member 433 on the top of the first motor locking member 431.

As shown in fig. 1, the first motor locking member 431 is sleeved outside the motor 41, the second motor locking member 432 is connected to the first motor locking member 431 through the output shaft of the motor 41, the first motor locking member 431 and the motor moving member 433 are fixed by screws, the adjusting knob 434 is screwed on the tail of the motor moving member 433 by threads, and the motor 41, the power control circuit board 441 and the main circuit board 444 are respectively connected by wires.

Optionally, as shown in fig. 2, 5, and 6, the crank body 1 further includes a narrow tube 12 and a middle tube 13, the lower end of the crank hook 11 is connected to the upper end of the narrow tube 12, the outer side of the lower portion of the narrow tube 12 is connected to the middle tube 13, the middle tube 13 is located inside the upper portion of the thick tube 15, a first adjusting mechanism 14 is disposed between the narrow tube 12 and the middle tube 13, the first adjusting mechanism 14 includes a locking sleeve 141 and an internal thread locking rotating member 142, the locking sleeve 141 is an opening, the locking sleeve 141 is located outside the narrow tube 12, the upper side of the locking sleeve 141 is a circular shape, the lower side of the locking sleeve is a twelve-angle flower shape, the bottom of the locking sleeve 141 is adapted to the inner surface of the middle tube 13, the section inside the internal thread locking rotating member 142 is a trapezoid, the inner surface of the internal thread locking rotating member 142 is connected to the outer surface of the locking sleeve 141, the inner surface of the lower, and the inner side of the bottom thick pipe 15 of the middle pipe 13 is provided with a middle pipe hexagonal fixing part 18, and a second adjusting mechanism 16 is arranged between the thick pipe 15 and the middle pipe 13.

The lower end of a hand crank hook 11 is fixedly connected with the upper end of a thin tube 12 through a blind rivet, and the thin tube 12 is movably connected with a middle tube 13 through a first adjusting mechanism 14.

The middle pipe 13 is movably connected with the thick pipe 15 through a second adjusting mechanism 16, and the thin pipe 12, the middle pipe 13 and the thick pipe 15 are all made of aluminum materials.

As shown in fig. 2, 5 and 6, the locking sleeve 141 is sleeved outside the thin tube 12 and inserted into the middle tube 13, the internal thread locking rotating member 142 is sleeved outside the locking sleeve 141, the bottom of the internal thread locking rotating member 142 is screwed outside the middle tube 13, the locking sleeve 141 can be locked outside the thin tube 12 due to the inner surface inclination of the internal thread locking rotating member 142, the thin tube 12 and the middle tube 13 are connected, the height between the thin tube 12 and the middle tube 13 can be adjusted, the height between the middle tube 13 and the thick tube can be adjusted by the second adjusting mechanism 16, the locking sleeve is suitable for different working scenes, the upper side of the locking sleeve 141 is circular and the lower side of the locking sleeve 141 is dodecagonal, the lower side of the locking sleeve 141 is connected with the inner wall of the middle tube 13, the locking sleeve 141 can not rotate together with the internal thread locking rotating member 142 to cause the phenomenon that the thin tube 12 is locked during, the shape of tubule hexagonal mounting 17 surface and the shape looks adaptation of well pipe 13 internal surface, and the shape of well pipe hexagonal mounting 18 surface and the shape looks adaptation of thick pipe 15 internal surface, can die the bottom lock of tubule 12 through tubule hexagonal mounting 17, avoid tubule 12 at the inside independent rotation of well pipe 13, and can die the bottom lock of well pipe 13 through well pipe hexagonal mounting 18, avoid well pipe 13 at the inside independent rotation of thick pipe 15, it is fixed more firm, the transmission effect is better.

Optionally, as shown in fig. 3, a charging interface 448 is installed at one side of the upper end of the housing 2 close to the thick pipe 15, the charging interface 448 is connected to the main circuit board 444 through a wire, the power control circuit board 441 is clamped on the insertion position of the housing 2, the surface of the power control circuit board 441 is embedded on the inner wall of the housing 2, and the power switch 442 is sleeved on the inner wall of the housing 2, half of the power switch 442 is located inside the housing 2, and the other half of the power switch 442 is located outside the housing 2.

The power control circuit board 441 is connected with the main circuit board 444 through a conducting wire, the inching button 445 is arranged on the inner side of the shell 2, a button is arranged on the inner side of the inching button 445 on the surface of the main circuit board 444, the button is connected with the main circuit board 444 through a conducting wire, the inching button 445 is sleeved on the surface of the button, the inching button 445 is fixed on a screw point convex cylinder of the shell 2 through a screw, and the two groups of the shells 2 are fixed through screws.

The surface of the main circuit board 444 is provided with a steering power supply, a steering switch 443 is installed outside the steering power supply, a battery holder 446 is arranged between the battery 447 and the casing 2, and the positive and negative electrodes of the battery holder 446 are electrically connected with the main circuit board 444.

As shown in fig. 3, the charging interface 448, the jog key 445, the battery 447, and the steering switch 443 are respectively connected to the main circuit board 444 through wires, the battery 447 is installed inside the battery holder 446, the battery holder is started up by long pressing the power switch 442, after the battery holder is started up, the jog key 445 is pressed to operate the motor 41, the motor 41 drives the second bevel gear 422 to rotate, the second bevel gear 422 is meshed with the first bevel gear 421 through a gear, the first bevel gear 421 drives the thick tube 15 to rotate, the crank handle hook 11 is rotated through the thick tube 15, so that the crank is in a working state, the thick tube 15 is connected to the housing 2 through the thick tube rotating shaft 3, the thick tube 15 is stable when rotating, the thick tube 15 can be rotated reversely when the steering switch 443 is toggled, requirements of different working states can be met, labor is saved, and the working efficiency is high.

Optionally, as shown in fig. 4, the first bevel gear 421 is fixedly connected to the outer side of the wide tube 15, two wide tube rotating shafts 3 are arranged between the wide tube 15 and the outer shell 2, the wide tube 15 is movably connected to the outer shell 2 through the wide tube rotating shafts 3, the first bevel gear 421 is engaged with the second bevel gear 422, the second bevel gear 422 is fixedly connected to an output shaft of the motor 41, the first motor locking member 431 is connected to the second motor locking member 432 through a screw, the motor moving member 433 is fixedly connected to the first motor locking member 431 through a screw, an adjusting knob 434 is clamped inside the outer shell 2 at the tail of the motor moving member 433, and the adjusting knob 434 is connected to the motor moving member 433 through a screw.

As shown in fig. 4, the adjusting knob 434 and the motor moving member 433 form a screw rod structure, the motor moving member 433 can be driven to move by rotating the adjusting knob 434, and the motor moving member 433 is connected with the motor 41 through the first motor locking member 431 and the second motor locking member 432, so that the motor 41 can be moved, and the second bevel gear 422 is driven to move and be separated from the first bevel gear 421, thereby avoiding touching the jog key 445 when not in use to enable the crank hook 11 to work, and the use is safer.

It should be noted that, the utility model relates to an electric hand crank, the user covers the internal thread locking rotating piece 142 on the outside of the locking sleeve 141, the bottom of the internal thread locking rotating piece 142 is screwed on the outside of the middle tube 13, because the internal surface of the internal thread locking rotating piece 142 is inclined, the locking sleeve 141 can be locked on the outside of the thin tube 12, and then the thin tube 12 and the middle tube 13 are connected, the height between the thin tube 12 and the middle tube 13 can be adjusted, the height between the middle tube 13 and the thick tube 15 can be adjusted by the same principle, the start-up is carried out by long pressing the power switch 442, after the start-up, the inching button 445 is pressed to make the motor 41 work, the second bevel gear 422 is driven to rotate by the motor 41, and the second bevel gear 422 is meshed with the first bevel gear 421, and then the first bevel gear 421 drives the thick tube 15 to rotate, the hand crank 11 is rotated by the thick tube 15, thick pipe 15 and shell 2 are connected through thick pipe axis of rotation 3 between, thick pipe 15 is more stable when rotating, can make thick pipe 15 counter rotation when stirring steering switch 443, can satisfy different operating condition's demand, can drive motor moving member 433 through rotation regulation knob 434 and remove, and motor moving member 433 is through first motor locking piece 431, second motor locking piece 432 is connected with motor 41, and then can make motor 41 remove, thereby drive second bevel gear 422 and remove and separate with first bevel gear 421, can make thick pipe 15 free rotation.

The above is only a preferred embodiment of the present invention, and is not intended to limit the present invention, and various modifications and changes will occur to those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. The utility model provides an electronic crank, includes crank body (1), movable mounting shell (2) of crank body (1) middle part outside symmetry, its characterized in that: crank body (1) includes crank hook (11), thick pipe (15), the internally mounted of shell (2) has electric drive (4), electric drive (4) are including movable mounting's motor (41), drive mechanism (42), electronic module (44), drive mechanism (42) are including first bevel gear (421) of the surface of the inboard thick pipe (15) of shell (2), second bevel gear (422) of motor (41) output shaft tip, electronic module (44) are including battery (447), card power control circuit board (441) and total circuit board (444) inboard in shell (2), electric drive (4) still include positioning mechanism (43), positioning mechanism (43) are including first motor locking piece (431) in the outside of motor (41), run through second motor locking piece (432) of motor (41) output shaft, A motor moving member (433) on top of the first motor locking member (431).

2. An electric hand crank according to claim 1, characterized in that: the crank body (1) further comprises a thin tube (12) and a middle tube (13), the lower end of a hook (11) of the crank is connected with the upper end of the thin tube (12), the middle tube (13) is connected with the outer side of the lower portion of the thin tube (12), the middle tube (13) is located on the inner side of the upper portion of a thick tube (15), a first adjusting mechanism (14) is arranged between the thin tube (12) and the middle tube (13), the first adjusting mechanism (14) comprises a locking sleeve (141) and an internal thread locking rotating piece (142), the locking sleeve (141) is an opening, the locking sleeve (141) is arranged on the outer side of the thin tube (12), the upper side of the locking sleeve (141) is in a twelve-angle flower shape and is matched with the inner surface shape of the middle tube (13), the internal thread locking rotating piece (142) is in a trapezoid shape, the inner surface of the internal thread locking rotating piece (142) is connected with the outer surface of the locking sleeve (141), and the internal surface of internal thread locking rotating member (142) lower part passes through threaded connection with well pipe (13) upper portion's surface, the inboard of pipe (13) is connected with tubule hexagonal mounting (17) in the bottom of tubule (12), and the inboard of the thick pipe in the bottom of well pipe (13) (15) is provided with well pipe hexagonal mounting (18), be provided with second adjustment mechanism (16) between thick pipe (15) and well pipe (13).

3. An electric hand crank according to claim 1, characterized in that: first bevel gear (421) are fixed in the outside of thick pipe (15), be provided with two thick pipe axis of rotation (3) between thick pipe (15) and shell (2), thick pipe (15) are through thick pipe axis of rotation (3) and shell (2) swing joint, first bevel gear (421) and second bevel gear (422) interlock mutually, second bevel gear (422) and the output shaft fixed connection of motor (41), first motor locking piece (431) pass through screwed connection with second motor locking piece (432), and motor moving member (433) pass through screw and first motor locking piece (431) fixed connection, the inside card of afterbody shell (2) of motor moving member (433) has adjust knob (434), adjust knob (434) and motor moving member (433) pass through threaded connection.

4. An electric hand crank according to claim 1, characterized in that: the utility model discloses a shell (2) is characterized in that the upper end of shell (2) is close to one side of thick pipe (15) and installs interface (448) that charges, it is connected through the wire between interface (448) and total circuit board (444) to charge, power control circuit board (441) card is on the position of inserting of shell (2), the surface of power control circuit board (441) inlays the inner wall cover in shell (2) and has switch (442).

5. An electric hand crank according to claim 1, characterized in that: the power control circuit board (441) is connected with the main circuit board (444) through a conducting wire, the inner side of the shell (2) is provided with a jog key (445), the inner side of the jog key (445) on the surface of the main circuit board (444) is provided with a button, the button is connected with the main circuit board (444) through a conducting wire, the jog key (445) is sleeved on the surface of the button, and the jog key (445) is fixed on a screw point convex cylinder of the shell (2) through a screw.

6. An electric hand crank according to claim 1, characterized in that: the surface of total circuit board (444) is provided with turns to the power, turns to the power outside and installs turn switch (443), be provided with battery frame (446) between battery (447) and shell (2), the positive negative pole and the total circuit board (444) electric connection of battery frame (446).

7. An electric hand crank according to claim 2, characterized in that: the lower end of the hand crank hook (11) is fixedly connected with the upper end of the thin tube (12), and the thin tube (12) is movably connected with the middle tube (13) through a first adjusting mechanism (14).

8. An electric hand crank according to claim 2, characterized in that: the middle pipe (13) is movably connected with the thick pipe (15) through a second adjusting mechanism (16), and the thin pipe (12), the middle pipe (13) and the thick pipe (15) are all made of aluminum materials.