WO2023137986A1

WO2023137986A1 - Pulley positioning method and axial positioning mechanism

Info

Publication number: WO2023137986A1
Application number: PCT/CN2022/102745
Authority: WO
Inventors: 覃柏深; 刘国良
Original assignee: 湖南星邦智能装备股份有限公司
Priority date: 2022-01-18
Filing date: 2022-06-30
Publication date: 2023-07-27
Also published as: CN114408771A

Abstract

A pulley positioning method, comprising: first, mounting a pulley assembly (5) into a gap between a side surface of an inner arm (7) and a side surface of an outer arm (6), and aligning an inner bearing ring of the pulley assembly (5) with a mounting hole (61) of the outer arm (6); next, inserting a positioning shaft (4) into a positioning hole (21) of a pulley shaft (2), and adjusting the angle of the positioning shaft (4) so that a positioning cap (41) of the positioning shaft (4) is in a stored state; then, inserting the pulley shaft (2) where the positioning shaft (4) has been mounted into the mounting hole (61) and the inner bearing ring of the pulley assembly (5); after that, rotating the positioning shaft (4) to adjust the positioning cap (41) to an unfolded state so as to position the pulley assembly (5); and finally, fixing the pulley shaft (2) and the positioning shaft (4). By rotating the positioning shaft (4) on the outer side of the outer arm (6), the positioning cap (41) can axially limit the pulley assembly (5), and a limiting portion can circumferentially limit the positioning cap (41), thereby ensuring the positioning firmness and reducing the positioning difficulty. Also provided is an axial positioning mechanism applied to the pulley positioning method.

Description

A pulley positioning method and axial positioning mechanism

This application claims the priority of the Chinese patent application with the application number 202210054354.9 and the title of the invention "A Pulley Positioning Method and Axial Positioning Mechanism" submitted to the China Patent Office on January 18, 2022, the entire contents of which are incorporated in this application by reference.

technical field

The invention relates to the technical field, in particular to a pulley positioning method. The present invention also relates to an axial positioning mechanism applicable to the above pulley positioning method.

Background technique

Existing aerial work platforms or cranes usually use wire ropes to drive the expansion and contraction of the boom, and the extension pulleys are arranged on the side of the boom. Because the side of the root of the inner arm has a slide block, the installation process needs to install the inner arm into the outer arm first, then install the pulley from the gap between the sides of the two arms, and finally position the pulley. The operation space of the pulley positioning process is narrow, which increases the difficulty of positioning the pulley and affects the firmness of the pulley positioning.

Therefore, how to reduce the difficulty of axial positioning of the pulley is a problem to be solved by those skilled in the art.

Contents of the invention

The purpose of the present invention is to provide a pulley positioning method, which can be operated outside the outer arm to realize the positioning of the pulley assembly, thereby reducing the difficulty of positioning the pulley assembly and improving the firmness of positioning. Another object of the present invention is to provide an axial positioning mechanism applied to the above pulley positioning method.

To achieve the above object, the present invention provides a pulley positioning method, comprising:

Install the pulley assembly into the gap between the side of the inner arm and the side of the outer arm, so that the bearing inner ring of the pulley assembly is aligned with the mounting hole of the outer arm;

Insert the positioning shaft into the positioning hole of the pulley shaft, one end of the positioning shaft is provided with a positioning cap for positioning the pulley assembly, adjust the angle of the positioning shaft, and make the positioning cap of the positioning shaft in a storage state;

inserting the pulley shaft with the positioning shaft installed into the mounting hole and the bearing inner ring of the pulley assembly;

Rotate the positioning shaft, adjust the positioning cap to the unfolded state to position the pulley assembly, the pulley shaft is located at the limit portion of the end surface at one end in the gap, and the limit portion limits the position of the positioning cap in the circumferential direction when the positioning cap is in the unfolded state;

Fix the pulley shaft and the positioning shaft.

Preferably, the limiting part is the limiting groove with a side opening, the positioning hole is located at the bottom of the limiting groove, and the axis of the positioning hole is a preset distance from the axis of the pulley shaft;

When the positioning cap is in a stored state, the projection of the positioning cap on the mating surface is completely within the projection range of the pulley shaft on the mating surface, and the mating surface is the plane where the end face of the pulley shaft located in the gap is located.

Preferably, the positioning cap includes two arc side sides, one of which is a positioning side and the other is a limiting side, and the distance between the positioning side and the axis of the positioning shaft is greater than the distance between the limiting side and the axis of the positioning shaft;

When the positioning cap is in the unfolded state, the projection of the positioning edge on the mating surface is outside the projection range of the pulley shaft on the plane.

Preferably, a bottom plate is provided at one end of the pulley shaft outside the gap;

The fixing of the pulley shaft and the positioning shaft includes:

The base plate is fixedly connected with the outer arm by fixing bolts.

The fixing of the pulley shaft and the positioning shaft includes:

The base plate is fixedly connected with the outer arm by fixing bolts.

Preferably, the end of the positioning shaft away from the positioning cap is provided with an external thread;

Said fixing said pulley shaft and said positioning shaft also includes:

The positioning shaft is fixed by a positioning nut, so that the positioning cap is attached to the bearing inner ring of the pulley assembly.

Preferably, the end of the positioning shaft away from the positioning cap is provided with a position indicating portion for indicating the position of the positioning cap.

Preferably, the position indicating portion is a position indicating protrusion extending away from the positioning cap, the cross section of the position indicating protrusion is semicircular, and the position indicating protrusion corresponds to the position of the positioning cap;

The rotating the positioning shaft, adjusting the positioning cap to the unfolded state to position the pulley assembly includes:

Rotate the positioning shaft by 180°, pull the positioning shaft along the axial direction of the positioning shaft, and make the positioning cap enter the limiting groove.

The present invention also provides a shaft positioning agency, which is used in any of the above -mentioned pulley positioning methods, including the wheel axis and the positioning shaft. The pulley shaft has a positioning hole that extends along the axis. The end surface of the pulley shaft is located at the end of the inner side of the outer arm. The limits of the positioning caps of the positioning cap are settled at the position of the positioning of the positioning cap.

In the pulley positioning method provided by the present invention, firstly, the pulley assembly is loaded into the gap between the side of the inner arm and the side of the outer arm, so that the bearing inner ring of the pulley assembly is aligned with the mounting hole of the outer arm; then the positioning shaft is inserted into the positioning hole of the pulley shaft, and one end of the positioning shaft is provided with a positioning cap for positioning the pulley assembly, and the angle of the positioning shaft is adjusted so that the positioning cap of the positioning shaft is in a stored state; Adjust the positioning cap to the unfolded state to position the pulley assembly. The pulley shaft is located at the end surface limit portion at one end of the gap. The limit portion will limit the positioning cap in the circumferential direction when the positioning cap is in the unfolded state; finally fix the pulley shaft and the positioning shaft.

The pulley positioning process can be completed on the outside of the outer wall. Turning the positioning shaft can make the positioning cap limit the pulley assembly in the axial direction, and at the same time, the limit part can limit the positioning cap in the circumferential direction, ensuring the firmness of positioning and reducing the difficulty of positioning.

The present invention also provides an axial positioning mechanism applied to the above pulley positioning method, which has the above advantages.

Description of drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following will briefly introduce the accompanying drawings required in the description of the embodiments or prior art. Obviously, the accompanying drawings in the following description are only embodiments of the present invention. For those of ordinary skill in the art, other accompanying drawings can also be obtained according to the provided drawings without creative work.

Fig. 1 is the flowchart of the pulley positioning method provided by the present invention;

Fig. 2 is a schematic structural view of the inner storage state of the axial positioning mechanism provided by the present invention;

Fig. 3 is a schematic structural view of the inner side of the axial positioning mechanism in Fig. 2;

Fig. 4 is a schematic structural view of the outer storage state of the axial positioning mechanism in Fig. 2;

Fig. 5 is a schematic structural view of the outward deployment state of the axial positioning mechanism in Fig. 2;

Fig. 6 is a schematic structural view of the pulley shaft in Fig. 2;

Fig. 7 is a schematic structural view of the positioning shaft in Fig. 2;

Fig. 8 is the structural representation of pulley assembly;

Fig. 9 is a cross-sectional view of the storage state of the axial positioning mechanism in Fig. 2;

Fig. 10 is a cross-sectional view of the deployed state of the axial positioning mechanism in Fig. 2;

Fig. 11 is a structural schematic diagram of a telescopic arm without an axial positioning mechanism;

Fig. 12 is a schematic structural view of a telescopic arm equipped with an axial positioning mechanism.

Wherein, reference numeral among Fig. 1 to Fig. 12 is:

Fixing bolt 1, pulley shaft 2, positioning nut 3, positioning shaft 4, pulley assembly 5, outer arm 6, inner arm 7, positioning hole 21, limiting groove 22, bottom plate 23, positioning cap 41, position indicating protrusion 42, mounting hole 61, positioning edge 411, limiting edge 412.

Detailed ways

The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only some, not all, embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

In order to enable those skilled in the art to better understand the solution of the present invention, the present invention will be further described in detail below in conjunction with the accompanying drawings and specific embodiments.

Please refer to Figure 1 to Figure 12.

The pulley positioning method provided by the present invention includes:

S1. Put the pulley assembly 5 into the gap between the side of the inner arm 7 and the side of the outer arm 6, so that the bearing inner ring of the pulley assembly 5 is aligned with the mounting hole 61 of the outer arm 6;

As shown in Figure 11, the inner arm 7 is inserted into the outer arm 6, and there is a gap between the two, and the pulley assembly 5 is installed in the gap, the installation method can refer to the prior art, and will not be repeated here.

S2, insert the positioning shaft 4 into the positioning hole 21 of the pulley shaft 2, one end of the positioning shaft 4 is provided with a positioning cap 41 for positioning the pulley assembly 5, adjust the angle of the positioning shaft 4, and make the positioning cap 41 of the positioning shaft 4 be in a storage state;

Optionally, the positioning hole 21 adopts an eccentric structure in the pulley shaft 2, that is, the axis of the positioning hole 21 is at a preset distance from the axis of the pulley shaft 2, and the preset distance is smaller than the radius difference between the pulley shaft 2 and the positioning hole 21. The positioning cap 41 is in a stowed state when it is rotated until the positioning hole 21 is close to the side of the axis of the pulley shaft 2 .

When the positioning cap 41 is in the storage state, the projection of the positioning cap 41 on the mating surface is completely within the projection range of the pulley shaft 2 on the mating surface, and the mating surface is the plane where the end face of the pulley shaft 2 is located in the gap.

At this time, the outer circumference of the positioning cap 41 will not exceed the outer circumference of the pulley shaft 2 , thus facilitating the installation of the pulley shaft 2 into the installation hole 61 .

S3. Insert the pulley shaft 2 with the positioning shaft 4 installed into the mounting hole 61 and the bearing inner ring of the pulley assembly 5;

The structure of the pulley shaft 2 installed with the positioning shaft 4 is shown in FIG. 2 , and the pulley shaft 2 is inserted into the mounting hole 61 and the inner ring of the bearing. At this time, the pulley assembly 5 can rotate around the pulley shaft 2, but the axial positioning mechanism does not axially limit the pulley assembly 5, as shown in Figure 9, the pulley assembly 5 can still move toward the inner arm 7 side.

S4, rotate the positioning shaft 4, adjust the positioning cap 41 to the expanded state, to position the pulley assembly 5, the end surface of the pulley shaft 2 at one end in the gap has a limit portion, and the limit portion performs a circumferential limit on the positioning cap 41 when the positioning cap 41 is in the unfolded state;

Rotating the positioning shaft 4 can adjust the positioning cap 41 to the unfolded state. In the unfolded state, the projection of one side of the positioning cap 41 on the mating surface is outside the projection range of the pulley shaft 2 on the plane. As shown in Figure 3 and Figure 10, the positioning cap 41 is located on the side of the pulley assembly 5 away from the outer arm 6, and limits the bearing inner ring of the pulley assembly 5.

Optionally, the limiting part is a limiting groove 22 with a side opening, and the positioning hole 21 is located at the bottom of the limiting groove 22 . The positioning cap 41 includes two arc sides, one of which is a positioning side 411 and the other is a limiting side 412 , the distance between the positioning side 411 and the axis of the positioning shaft 4 is greater than the distance between the limiting side 412 and the axis of the positioning shaft 4 . The radian of the side wall of the limiting groove 22 is equal to the radian of the limiting edge 412 , and the distance between the side wall of the limiting groove 22 and the axis of the positioning hole 21 is equal to the distance between the limiting edge 412 and the axis of the positioning shaft 4 . Therefore, when the positioning cap 41 is rotated to a position corresponding to the limiting groove 22, the positioning cap 41 can enter the limiting groove 22, and the sidewall of the limiting groove 22 can limit the positioning cap 41 through the limiting edge 412 to prevent the positioning cap 41 from rotating.

Optionally, the end of the positioning shaft 4 away from the positioning cap 41 is provided with a position indicating portion for indicating the position of the positioning cap 41 , and the assembler can determine the position of the positioning cap 41 through the position indicating portion.

Optionally, the position indicating portion is a position indicating protrusion 42 extending away from the positioning cap 41. As shown in FIG. 4 and FIG. In the process of positioning the pulley assembly 5, the positioning shaft 4 is rotated by 180°, and then the positioning shaft 4 is pulled along the axial direction of the positioning shaft 4, so that the positioning cap 41 enters the limiting groove 22 to realize the positioning of the pulley assembly 5, and at the same time, the positioning cap 41 is limited by the limiting groove 22.

S5, fixed pulley shaft 2 and positioning shaft 4.

Optionally, one end of the pulley shaft 2 outside the gap is provided with a bottom plate 23 , the bottom plate 23 has a fixing hole penetrating through the thickness direction, and the outer arm 6 is provided with a threaded hole on the periphery of the mounting hole 61 . When fixing the pulley shaft 2, the fixing bolt 1 passes through the fixing hole and links to each other with the threaded hole. Of course, the user can also fix the bottom plate 23 and the outer arm 6 by means of welding or the like as required, which is not limited here.

Optionally, the end of the positioning shaft 4 away from the positioning cap 41 is provided with an external thread. After rotating to the unfolded state, the external thread of the positioning shaft 4 extends out of the gap between the outer arm 6 and the inner arm 7 . The assembler connects the positioning nut 3 with the positioning shaft 4, and the bolt pretightening force is directed toward the outside of the gap along the axial direction of the positioning shaft 4. The pre-tightening force of the bolts makes the positioning cap 41 closely fit the bearing inner ring of the pulley assembly 5 .

In this embodiment, the pulley positioning method only needs to be operated outside the outer arm 6, the pulley shaft 2 is connected to the inner ring of the bearing of the pulley assembly 5, and then the positioning shaft 4 is rotated to axially position the pulley assembly 5, and finally the pulley shaft 2 and the positioning shaft 4 are fixed to complete the positioning of the pulley assembly 5. The operation process is simple, the positioning difficulty is low, and at the same time, the firmness of the positioning of the pulley assembly 5 can be ensured.

The structure of the axial positioning mechanism provided by the present invention is shown in FIGS. 1 to 4 , including a pulley shaft 2 and a positioning shaft 4 . One end of pulley shaft 2 is provided with base plate 23, and outer arm is provided with mounting hole, and pulley shaft 2 is inserted in the mounting hole, and base plate 23 is fitted with the outside of outer arm, and is connected by fixing bolt 1 between the outer arm. The pulley assembly 5 includes a bearing, and the bearing is installed on the outer periphery of the pulley shaft 2 . The pulley shaft 2 has a positioning hole 21 extending axially therein, and the positioning shaft 4 is installed in the positioning hole 21 .

One end of the positioning shaft 4 located at the inner side of the outer arm is provided with a positioning cap 41 . The plane where the end face of the pulley shaft 2 is located at the inner side of the outer wall is a matching surface, and the position of the positioning cap 41 can be adjusted by rotating the positioning shaft 4, so that the positioning cap 41 is switched between the unfolded state and the stored state. Positioning cap 41 is located on the side of the pulley assembly 5 away from the side of the bottom plate 23. When the positioning cap 41 is in the collection state, the projection of the positioning cap 41 is completely located on the projection range of the pulley 2 on the coordination surface. The projection of part of the hat 41 on the surface is located on the projection of the pulley 2 on the coordinated surface. This part can locate axial positioning of the pulley assembly 5. The end face of the pulley shaft 2 located at the inner side of the outer arm is provided with a limiting portion, which can position the positioning cap 41 in a circumferential direction, so that the positioning cap 41 is always in an unfolded state when the pulley rotates. In addition, one end of the positioning shaft 4 located outside the outer arm is connected to the positioning part, and the positioning part fixes the positioning shaft 4 .

Optionally, the limiting part is a limiting groove 22 with a side opening, and the positioning hole 21 is located at the bottom of the limiting groove 22 . As shown in FIG. 5 , the top and upper sides of the limiting groove 22 are open. When the positioning cap 41 is located in the limiting groove 22, it is in the unfolded state; when the positioning cap 41 is in the storage state, it is located outside the limiting groove 22, and the positioning cap 41 fits with the end face of the pulley shaft 2. At this time, the end face of the pulley shaft 2 supports the positioning cap 41 to ensure that it will not enter the limiting groove 22. During the process of switching from the stored state to the unfolded state, the positioning cap 41 enters the limiting groove 22 from the top and protrudes from the side opening at the same time to position the pulley assembly 5 . The sidewall of the limiting groove 22 can limit the positioning cap 41 to prevent it from rotating. Certainly, the position limiting portion may also adopt a structure such as a position limiting protrusion, which is not limited here.

Optionally, the positioning cap 41 includes two arc sides, and the central angle corresponding to each arc side is less than 180°, so the positioning cap 41 forms a leaf-like structure. One arc side of the positioning cap 41 is a positioning side 411 , and the other is a limiting side 412 . The distance between the positioning side 411 and the axis of the positioning shaft 4 is greater than the distance between the limiting side 412 and the axis of the positioning shaft 4. When the positioning cap 41 is in the unfolded state, the positioning side 411 is located outside the limiting groove 22 to position the pulley assembly 5. In addition, the sidewall of the limiting groove 22 is also arranged along an arc, and the shape of the arc is the same as that of the limiting edge 412 . The distance between the side wall of the limiting groove 22 and the axis of the positioning hole 21 is equal to the distance between the limiting edge 412 and the axis of the positioning shaft 4, and is smaller than the radius of curvature of the limiting edge 412, so the side wall of the limiting groove 22 can limit the positioning cap 41. Of course, the user can also set the positioning cap 41 and the limiting groove 22 into other shapes according to needs, which is not limited here.

Optionally, the positioning hole 21 adopts an eccentric structure in the pulley shaft 2, that is, the axis of the positioning hole 21 is at a preset distance from the axis of the pulley shaft 2, and the preset distance is smaller than the radius difference between the pulley shaft 2 and the positioning hole 21.

Optionally, the positioning part is a positioning nut 3, and the end of the positioning shaft 4 away from the positioning cap 41 is provided with an external thread, and the positioning nut 3 and the positioning shaft 4 are connected by threads. Of course, the user can also use a fixing card or a fixing pin to axially position the positioning shaft 4 .

Optionally, one end of the positioning shaft 4 located outside the outer arm is provided with a position indicator, which can indicate the position of the positioning cap 41 . The assembler can determine whether the positioning cap 41 can enter into the limiting groove 22 through the position of the position indicating part.

Optionally, the position indicating part is a position indicating protrusion 42 extending away from the positioning cap 41, and the cross section of the position indicating protrusion 42 is semicircular. The positioning side 411 of the positioning cap 41 is located in a fan-shaped area centered on a point on the axis of the positioning shaft 4 , and the fan-shaped area is located in the same direction as the semicircle of the position-indicating protrusion 42 . Therefore, the assembler can determine the angle of the positioning cap 41 according to the angle of the position indicating protrusion 42 .

In addition, when the positioning cap 41 is in the stowed state, the height of the position indicating protrusion 42 is relatively low. The operator continues to rotate the positioning shaft 4 until the positioning cap 41 enters the positioning groove. Simultaneously, the position indicating protrusion 42 will also extend toward the outside of the bottom plate 23 , and at this time, the position indicating protrusion 42 can extend out of the positioning nut 3 . The assembler can also judge whether the axial positioning mechanism has completed the positioning according to the height of the position indicating protrusion 42 .

In this embodiment, the axial positioning mechanism is provided with a positioning shaft 4 in the pulley shaft 2 , and the positioning cap 41 on the positioning shaft 4 cooperates with the limit groove 22 on the pulley shaft 2 to axially position the pulley assembly 5 . At the same time, during the positioning process, only the assembler needs to rotate the positioning shaft 4 on the outside of the outer arm so that the positioning cap 41 enters the limiting groove 22, and finally the positioning nut 3 is installed from the outside to fix the positioning shaft 4. The whole positioning process is carried out on the outside of the outer arm, which reduces the difficulty of operation and improves the reliability of positioning.

It should be noted that in this specification, relational terms such as first and second are only used to distinguish one entity from several other entities, and do not necessarily require or imply any such actual relationship or order between these entities.

The pulley positioning method and the axial positioning mechanism provided by the present invention have been introduced in detail above. In this paper, specific examples are used to illustrate the principle and implementation of the present invention, and the descriptions of the above embodiments are only used to help understand the method and core idea of the present invention. It should be pointed out that for those skilled in the art, without departing from the principle of the present invention, some improvements and modifications can be made to the present invention, and these improvements and modifications also fall within the protection scope of the claims of the present invention.

Claims

A pulley positioning method is characterized in that, comprising:

Put the pulley assembly (5) into the gap between the side of the inner arm (7) and the side of the outer arm (6), so that the bearing inner ring of the pulley assembly (5) is aligned with the mounting hole (61) of the outer arm (6);

Insert the positioning shaft (4) into the positioning hole (21) of the pulley shaft (2), one end of the positioning shaft (4) is provided with a positioning cap (41) for positioning the pulley assembly (5), adjust the angle of the positioning shaft (4), and make the positioning cap (41) of the positioning shaft (4) in a stored state;

Insert the pulley shaft (2) with the positioning shaft (4) installed into the mounting hole (61) and the bearing inner ring of the pulley assembly (5);

Rotate the positioning shaft (4), adjust the positioning cap (41) to the unfolded state to position the pulley assembly (5), the end surface of the pulley shaft (2) at one end in the gap has a limiting portion, and the limiting portion performs circumferential positioning on the positioning cap (41) when the positioning cap (41) is in the unfolded state;

Fix the pulley shaft (2) and the positioning shaft (4).
The pulley positioning method according to claim 1, wherein the limiting part is a limiting groove (22) having a side opening, the positioning hole (21) is located at the bottom of the limiting groove (22), and the axis of the positioning hole (21) is at a preset distance from the axis of the pulley shaft (2);

When the positioning cap (41) is in a stored state, the projection of the positioning cap (41) on the mating surface is completely within the projection range of the pulley shaft (2) on the mating surface, and the mating surface is the plane where the end face of one end of the pulley shaft (2) located in the gap is located.
The pulley positioning method according to claim 2, wherein the positioning cap (41) comprises two arc sides, one of which is a positioning side (411), and the other is a limiting side (412), and the distance between the positioning side (411) and the axis of the positioning shaft (4) is greater than the distance between the limiting side (412) and the axis of the positioning shaft (4);

When the positioning cap (41) is in the unfolded state, the projection of the positioning edge (411) on the mating surface is outside the projection range of the pulley shaft (2) on the plane.
The pulley positioning method according to claim 1, characterized in that, one end of the pulley shaft (2) outside the gap is provided with a bottom plate (23);

The fixing of the pulley shaft (2) and the positioning shaft (4) includes:

The bottom plate (23) is fixedly connected with the outer arm (6) by fixing bolts (1).
The pulley positioning method according to claim 4, characterized in that, the end of the pulley shaft (2) outside the gap is provided with a bottom plate (23);

The fixing of the pulley shaft (2) and the positioning shaft (4) includes:

The bottom plate (23) is fixedly connected with the outer arm (6) by fixing bolts (1).
The pulley positioning method according to claim 5, characterized in that, the end of the positioning shaft (4) away from the positioning cap (41) is provided with an external thread;

Said fixing said pulley shaft (2) and said positioning shaft (4) also includes:

The positioning shaft (4) is fixed by the positioning nut (3), so that the positioning cap (41) is attached to the bearing inner ring of the pulley assembly (5).
The pulley positioning method according to any one of claims 2 to 6, characterized in that, the end of the positioning shaft (4) away from the positioning cap (41) is provided with a position indicator for indicating the position of the positioning cap (41) (41).
The pulley positioning method according to claim 7, wherein the position indicating part is a position indicating protrusion (42) extending away from the positioning cap (41), the cross section of the position indicating protrusion (42) is semicircular, and the position indicating protrusion (42) corresponds to the position of the positioning cap (41);

The rotating the positioning shaft (4), adjusting the positioning cap (41) to the unfolded state to position the pulley assembly (5), includes:

The positioning shaft (4) is rotated by 180°, and the positioning shaft (4) is pulled along the axial direction of the positioning shaft (4), so that the positioning cap (41) enters the limiting groove (22).
An axial positioning mechanism, which is applied to the pulley positioning method described in any one of claims 1 to 8, is characterized in that it comprises a pulley shaft (2) and a positioning shaft (4), the pulley shaft (2) has a positioning hole (21) extending in the axial direction, the positioning shaft (4) is installed in the positioning hole (21), and one end of the positioning shaft (4) located on the inner side of the outer arm (6) is provided with a positioning cap (41) for axially positioning the pulley assembly (5). The end face of the inner side of the outer arm (6) is provided with a limiting portion for circumferentially limiting the positioning cap (41), and the positioning shaft (4) is fixed at the outer end of the outer arm (6) by the positioning portion.