WO2018036012A1

WO2018036012A1 - Miter saw and movable barrier positioning mechanism thereof

Info

Publication number: WO2018036012A1
Application number: PCT/CN2016/107681
Authority: WO
Inventors: Xiwan SONG; Yingping SHAO
Original assignee: Ningbo Defeng Power Technology Co., Ltd.
Priority date: 2016-08-26
Filing date: 2016-11-29
Publication date: 2018-03-01
Also published as: CN205927347U; DE202017004268U1

Abstract

Disclosed are a miter saw and a movable barrier positioning mechanism thereof. The movable barrier positioning mechanism comprises: a base (1); an operating rotary table (3) which is mounted to the base (1) and is swingingly rotatable with respect to the base (1) in a horizontal plane, a kerf (31) being provided in an upper surface of the operating rotary table (3); a fixed barrier (2) which is fixedly mounted to the base (1), a longitudinal direction of the fixed barrier (2) being in the horizontal plane and perpendicular to a direction along which the kerf (31) extends when the miter saw is in a vertical cutting position; and a movable barrier (4) which is mounted into the fixed barrier (2) in such a manner as to be movable in the longitudinal direction of the fixed barrier (2); wherein a cam surface is formed on an outer peripheral surface of the operating rotary table (3), and a cam follower (41) cooperating with the cam surface is provided on one end of the movable barrier (4) far from the kerf (31). When the operating rotary table (3) is swingingly rotated, the cam follower (41) is guided by the cam surface so that the movable barrier (4) is moved in the longitudinal direction of the fixed barrier (2). The movable barrier positioning mechanism is simple in structure, as well as safe and convenient to use.

Description

MITER SAW AND MOVABLE BARRIER POSITIONING MECHANISM THEREOF

Field of the Utility Model

The present utility model relates to a cutting device for performing a cutting operation on a workpiece, and specifically relates to a miter saw.

Background of the Utility Model

As a cutting tool that is applied widely, a miter saw, also referred to as a miter cutter, can be used to cut a workpiece at different angles. Fig. 1 shows a miter saw which mainly includes a base 10, an operating rotary table 30, a workpiece barrier 20, a rocking bar 40, a cutter head assembly 50 and so on. The operating rotary table 30 is substantially cylindrical. A linear kerf is provided in an upper surface (a working surface) of the operating rotary table 30. The operating rotary table 30 is mounted and supported to the base 10, and is swingingly rotatable with respect to the base 10 in a horizontal plane and lockable at any angle. The workpiece barrier 20 is fixedly mounted to the base 10, and the worpiece is positioned by a workpiece positioning surface of the workpiece barrier 20. Through the rocking bar 40, the cutter head assembly 50 not only can make a pitching motion but also can be rotated in the horizontal plane so that a main plane of a saw blade in the cutter head assembly 50 is aligned with the kerf. Further, the cutter head assembly 50 in miter saws of certain types can also make a heeling (rolling) motion so that the main plane of the saw blade is inclined with respect to the operating rotary table.

According to requirements of safety regulations, when the miter saw performs vertical cutting (the kerf and the main plane of the saw blade are perpendicular to the workpiece positioning surface of the workpiece barrier) , a distance from one end of the workpiece positioning surface of the workpiece barrier closer to the saw blade (or the kerf) to the main plane of the saw blade should be smaller than a prescribed dimension (for example, 8 mm) . If the workpiece barrier is stationary, when the miter saw performs angular cutting (the operating rotary table is swingingly rotated in the horizontal plane to leave the vertical cutting position and/or the main plane of the saw blade is inclined with respect to the operating rotary table) , it can not be ensured that the saw blade will not interfere with the workpiece barrier. As a result, in order to take the requirements of the safety regulations and practicability of the miter saw into consideration concurrently, the workpiece barrier is generally constituted by a fixed barrier and a movable barrier. When the vertical cutting is performed by the miter saw, the movable barrier is fixed at a position closer to the saw blade in a longitudinal direction of the movable barrier to ensure that a distance between the end closer to the saw blade of the movable barrier and the main plane of the saw blade satisfies the requirements of the safety regulations. When the angular cutting is performed by the miter saw, the movable barrier is moved to a position farther from the saw blade in the longitudinal direction of the movable barrier and fixed. However, in most of the existing miter saws of this kind, the position of the movable barrier needs to be repeatedly adjusted by the user according to the operating requirement, which causes trouble to the user, and may incur a potential danger because the user can not remember to adjust the movable barrier at first and then perform cutting every time, and the movable barrier is also likely to be damaged.

To overcome the disadvantages mentioned above, a number of miter saws having a movable barrier capable of being automatically extended and retracted have been raised presently. For example, Chinese patent publication No. CN103978269A discloses a structure in which a movable barrier is driven to be automatically extended and retracted using a slot in an operating rotary table. Such structure can take the requirements of the safety regulations and practicability of the product into consideration concurrently. However, since an elongate slot is opened in a middle portion of an upper surface of the operating rotary table, aesthetics of the product will be influenced seriously. Further, requirements for shape accuracy, position accuracy, and maintenance level of the slot are very strict. Excessively large deviation of accuracy will lead to an excessively large movement gap or inflexible movement of the movable barrier, even result in deadlock and make the movable barrier immovable. If chips in the slot are not cleared up timely, it is also possible that the movable barrier is moved inflexibly or can not be moved.

Summary of the Utility Model

In view of the disadvantages in the prior art, the present utility model aims to provide a movable barrier positioning mechanism used in a miter saw. The movable barrier positioning mechanism has a simple and reasonable structure and can be used safely, conveniently and reliably, and aesthetics of the miter saw will not be influenced.

In order to achieve the above object, the present utility model provides a movable barrier positioning mechanism used in a miter saw, and the movable barrier positioning mechanism comprises: a base； an operating rotary table which is mounted to the base and is swingingly rotatable with respect to the base in a horizontal plane, a kerf being provided in an upper surface of the operating rotary table； a fixed barrier which is fixedly mounted to the base, a longitudinal direction of the fixed barrier being in the horizontal plane and perpendicular to a direction along which the kerf extends when the miter saw is in a vertical cutting position, the fixed barrier having a workpiece positioning surface perpendicular to the horizontal plane； and a movable barrier which is mounted into the fixed barrier in such a manner as to be movable in the longitudinal direction of the fixed barrier, wherein a cam surface is formed on an outer peripheral surface of the operating rotary table, a cam follower cooperating with the cam surface is provided on one end of the movable barrier far from the kerf, and when the operating rotary table is swingingly rotated, the cam follower is guided by the cam surface so that the movable barrier is moved in the longitudinal direction of the fixed barrier.

Preferably, the movable barrier positioning mechanism further includes a presser which is used to apply a force pressing the cam follower against the outer peripheral surface of the operating rotary table to the movable barrier.

Preferably, the presser is a spring provided between the movable barrier and the fixed barrier.

Preferably, the cam surface is constituted by two convex segments and one concave segment smoothly connecting the two convex segments together.

Preferably, mounting columns with threaded holes are provided in the fixed barrier, the movable barrier is provided with long holes extending in the longitudinal direction of the fixed barrier at positions corresponding to the mounting columns, and the movable barrier is mounted to the mounting columns via mounting screws penetrating through the long holes.

Preferably, a retreat groove is formed at a position corresponding to the cam follower in a surface of the base facing the outer peripheral surface of the operating rotary table, and when the operating rotary table is swingingly rotated from the vertical cutting position, at least a part of the cam follower enters into the retreat groove in a direction away from the kerf.

Preferably, the cam follower is a cylindrical cam driven pin provided at the bottom of the movable barrier.

Preferably, the cam follower is provided at the bottom of the movable barrier and constituted by a fixed shaft and a rotary sleeve nested on the fixed shaft, and the rotary sleeve is rotated when the cam follower is guided by the cam surface.

Preferably, the movable barrier has a workpiece positioning surface, and the workpiece positioning surface of the movable barrier is coplanar with the workpiece positioning surface of the fixed barrier.

Preferably, the number of the movable barrier is two, the two movable barriers are provided on both sides of the kerf, and two cam surfaces respectively corresponding to cam followers of the two movable barriers are formed on the outer peripheral surface of the operating rotary table.

Correspondingly, the utility model provides a miter saw comprising the movable barrier positioning mechanism described above.

The present utility model causes the movable barrier to be automatically withdrawn in an operating state desired to keep away from the saw blade by providing the cam surface on the outer peripheral surface of the operating rotary table and using the cam surface to guide the movable barrier to be moved in the longitudinal direction of the fixed barrier so that safety, convenience and aesthetics of the miter saw are guaranteed simultaneously.

Brief Description of the Drawings

Fig. 1 shows an integral structure of a miter saw according to the prior art；

Fig. 2 is an exploded perspective view of a movable barrier positioning mechanism according to an preferred embodiment of the present utility model, wherein a left portion of a fixed barrier is cut through to show an internal structure of the fixed barrier；

Figs. 3A to 3C show the movable barrier positioning mechanism according to the preferred embodiment of the present utility model when the miter saw is in a vertical cutting position, wherein Fig. 3A is a perspective view, Fig. 3B is a sectional view vertically taken along a longitudinal direction of the fixed barrier, and Fig. 3C is a sectional view horizontally taken along the bottom of the fixed barrier； and

Figs. 4A to 4C show the movable barrier positioning mechanism according to the preferred embodiment of the present utility model when the miter saw is in an angular cutting position, wherein Fig. 4A is a perspective view, Fig. 4B is a sectional view vertically taken along the longitudinal direction of the fixed barrier, and Fig. 4C is a sectional view horizontally taken along the bottom of the fixed barrier.

Detailed Description of the Preferred Embodiments

Specific embodiments of the present utility model will be described below in connection with the drawings. In the concrete description of the embodiments, a front-rear direction means a direction in which a miter saw is close to and far from a user, and a side close to the user of the miter saw is referred to as a front side； an up-down direction means a height direction of the miter saw； a left-right direction means a widthwise direction of the miter saw, wherein a left side refers to a left hand side of the user and a right side refers to a right hand side of the user. The front-rear direction, the left-right direction and the up-down direction are orthogonal to one another.

With reference to Fig. 2 and Figs. 3A to 3C, a movable barrier positioning mechanism according to the present preferred embodiment includes a base 1, a fixed barrier 2, an operating rotary table 3, a movable barrier 4, an urging spring 5, mounting screws 6 and so on.

The base 1 includes left and

right stands

1A and 1B which are respectively provided on left and right sides of the operating rotary table 3 and protrude upward as well as a support portion 1C which is provided under the operating rotary table 3 to support the operating rotary table 3. The left stand 1A, the right stand 1B and the support portion 1C may be formed into an integral structure. A retreat groove 11 is formed in an upper portion of a right side surface of the left stand 1A (the right side surface faces an outer peripheral surface of the operating rotary table 3) . The retreat groove 11 is located correspondingly to a cam driven pin 41 to be described hereinafter.

The operating rotary table 3 is mounted to the support portion 1C of the base 1 and swingingly rotatable with respect to the base 1 in a horizontal plane. A linear kerf 31 is provided in an upper surface of the operating rotary table 3. As shown in Figs. 3A and 3C, when the miter saw is in a vertical cutting position, the linear kerf 31 extends forward (downward in Fig. 3C) .

A cam surface is formed on a left side outer peripheral surface of the operating rotary table 3. As shown in Figs. 2 and 4A, the cam surface is at least formed in a middle portion of the left side outer peripheral surface of the operating rotary table 3 in the front-rear direction and at least located in an upper portion on the left side outer peripheral surface of the operating rotary table 3. The cam surface is constituted by a front convex segment 32 and a rear convex segment 33 as well as an intermediate concave segment 34 smoothly connecting the front convex segment 32 and the rear convex segment 33 together. The front convex segment 32 and the rear convex segment 33 are smoothly connected to the peripheral surface of the operating rotary table 3 respectively.

The fixed barrier 2 is fixedly mounted to the left stand 1A and the right stand 1B of the base 1 via screws 51 and the like. A longitudinal direction of the fixed barrier 2 coincides with the left-right direction. A workpiece positioning surface 21 perpendicular to the horizontal plane is machined on a front side of the fixed barrier 2.

A cavity is formed in a part of a left portion of the fixed barrier 2 located above the operating rotary table 3. A space 23 for accommodating the urging spring 5 is formed in an upper portion of the cavity. A space 22 for accommodating the movable barrier 4 and permitting the movable barrier 4 to be moved leftward and rightward is formed in a lower portion of the cavity. A support rib 24 is provided on a right end of the space 23 of the fixed barrier 2. Two step-like mounting columns 25 with threaded holes are provided in the left-right direction within the space 22 of the fixed barrier 2.

A longitudinal direction of the movable barrier 4 also coincides with the left-right direction. Long holes 42 extending in the left-right direction are formed at positions corresponding to the two step-like mounting columns 25 in the movable barrier 4, and the long holes 42 may be waist-like holes. The movable barrier 4 is fixed to the two step-like mounting columns 25 of the fixed barrier 2 via screws 6 penetrating through the long holes 42 and respective washers. A height of a step portion of each of the step-like mounting columns 25 is slightly larger than a depth (a height) of each of the long holes 42 and an outer diameter of the step portion is slightly smaller than a width of the long holes 42 so that the movable barrier 4 may be moved leftward and rightward while being guided by the step portion. In other words, the movable barrier 4 is mounted into the fixed barrier 2 in such a manner that the movable barrier 4 is movable leftward and rightward in the longitudinal direction of the fixed barrier 2 so as to be extendable and retractable with respect to the fixed barrier 2.

Furthermore, a support plate 43 is provided on an upper surface of the movable barrier 4 and located on a rear side of the long holes 42. When the movable barrier 4 is mounted into the fixed barrier 2, the urging spring 5 as an example of a presser is sandwiched between the support rib 24 and the support plate 43 so as to apply a rightward force to the movable barrier 4 all the time.

The cam driven pin 41 as an example of a cam follower is provided at the bottom of a left end of the movable barrier 4. In the present embodiment, the cam driven pin 41 is a circular cylinder. A diameter of the circular cylinder is smaller than an opening width of the retreat groove 11. When the movable barrier 4 is mounted into the fixed barrier 2, the cam driven pin 41 is kept being pressed against (the cam surface on) the outer peripheral surface of the operating rotary table 3 under the action of the urging spring 5.

A step surface is formed on a front side surface of the movable barrier 4, and as shown in Figs. 3A and 4A, when the movable barrier 4 is mounted into the fixed barrier 2, a right portion of the front side surface of the movable barrier 4 functions as a workpiece positioning surface of the movable barrier 4. The workpiece positioning surface of the movable barrier 4 and the workpiece positioning surface 21 of the fixed barrier 2 are coplanar with each other and take part in the positioning operation of a workpiece together. A left portion of the front side surface of the movable barrier 4 is at least partially covered by a front wall surface of the fixed barrier 2.

In operation, as shown in Figs. 3A to 3C, when the miter saw is in the vertical cutting position, the cam driven pin 41 is pressed against the intermediate concave segment 34 of the cam surface under the action of the urging spring 5. The movable barrier 4 protrudes rightward out of the fixed barrier 2 to a maximum extent. At this time, a right end of the movable barrier 4 is located at a position closest to a saw blade in the left-right direction, and the requirements of the safety regulations are satisfied. When the miter saw is adjusted to make angular cutting, the operating rotary table 3 is required to be swingingly rotated. As shown in Figs. 4A to 4C, when the operating rotary table 3 is swingingly rotated rightward (counterclockwise) , the cam driven pin 41 is moved leftward against an elastic force of the urging spring 5 while being guided by the cam surface, passes the rear convex segment 33, and then reaches the peripheral surface portion of the operating rotary table 3 (in case of a small angle, the cam driven pin 41 may stay on the rear convex segment 33) . At this time, at least a part of the cam driven pin 41 enters into the retreat groove 11. At the same time, since the right end of the movable barrier 4 is moved leftward together with the cam driven pin 41, the movable barrier 4 is prevented from interfering with the saw blade and the requirements of the safety regulations are guaranteed. Likewise, when the operating rotary table 3 is swingingly rotated leftward (clockwise) , the right end of the movable barrier 4 is automatically moved leftward together with the cam driven pin 41, and thus the movable barrier 4 is prevented from interfering with the saw blade. Contrarily, when the miter saw is desired to return to the vertical cutting position from the angular cutting position, the cam driven pin 41 is moved rightward under the action of the elastic force of the urging spring 5 while being guided by the cam surface of the operating rotary table 3 so that the right end of the movable barrier 4 automatically returns to the position closest to the saw blade in the left-right direction accordingly.

As described above, in the present utility model, the movable barrier 4 is mounted into the fixed barrier 2 in such a manner as to be movable in the longitudinal direction of the fixed barrier 2. The cam surface is formed on the outer peripheral surface of the operating rotary table 3, and the cam driven pin 41 cooperating with the cam surface is provided to the movable barrier 4. As a result, when the operating rotary table 3 is swingingly rotated, the position of the movable barrier 4 in the left-right direction, i.e., the distance between the movable barrier 4 and the saw blade in the left-right direction, is automatically changed via the cam driven pin 41 by the cam surface. In this way, the movable barrier 4 can be automatically withdrawn in an operating state in which the movable barrier 4 needs to keep away from the saw blade (an angular cutting state) and can be moved to a position closer to the saw blade in an operating state in which the movable barrier 4 does not need to be withdrawn (a vertical cutting state) . Therefore, safety and convenience are ensured simultaneously. Meanwhile, since it is not required to open a slot in the upper surface of the operating rotary table 3, aesthetics of the miter saw will not be influenced, and it is not necessary to concern about a case in which the movable barrier 4 is moved inflexibly or can not be moved.

Moreover, since the presser 5 applying the rightward force to the movable barrier 4 is provided, it can be ensured that the movable barrier 4 is kept in contact with the outer peripheral surface of the operating rotary table 3, and positioning of the movable barrier 4 is guaranteed.

Additionally, since the retreat groove 11 is formed in the surface of the base 1 facing the outer peripheral surface of the operating rotary table 3 and located correspondingly to the cam driven pin 41, a point of the cam surface farthest from a center of the operating rotary table 3 may be located on the peripheral surface of the operating rotary table 3. In this way, a distance between the outer peripheral surface of the operating rotary table 3 and the surface of the base 1 facing said outer peripheral surface will not be excessively large, a depth by which the cam surface is recessed from the outer peripheral surface of the operating rotary table 3 may be decreased, and the influence on aesthetics can be reduced. Furthermore, since the retreat groove 11 is covered by the fixed barrier 2 (as shown in Fig. 3C) when viewed from above, the retreat groove 11 itself has no influence on aesthetics of the miter saw.

Modifications

Although the preferred embodiment of the present utility model has been described in detail hereinbefore, the present utility model is not limited to this. Those skilled in the art can make various alterations and modifications to the preferred embodiment within the scope of the present utility model.

For example, although the movable barrier and the corresponding cam surface are only provided on a left side of the kerf in the above embodiment, the movable barrier and the corresponding cam surface may also be provided on a right side of the kerf. Further, movable barriers may be provided on the left and right sides of the kerf respectively. In this case, two cam surfaces respectively corresponding to cam followers of the two movable barriers are formed on the outer peripheral surface of the operating rotary table.

Although the cam follower is the cylindrical cam driven pin in the above embodiment, the cam follower may take other shapes such as a semi cylinder, a cubic cylinder, an irregular shape and the like. Further, in order that the movable barrier is moved flexibly and smoothly, the cam follower may be constituted by a fixed shaft and a rotary sleeve nested on the fixed shaft. The cam follower is in contact with the cam surface of the operating rotary table via the rotary sleeve. Here, the rotary sleeve is rotated under the action of a frictional force by the cam surface, and thus a resistance to motion can be reduced.

Although the cam surface of the operating rotary table is formed by the front and rear convex segments smoothly connected to the peripheral surface portion of the operating rotary table respectively as well as the intermediate concave segment in the above embodiment, the cam surface may be designed into other shapes as actually required.

Although the cam surface is only formed in the upper portion of the outer peripheral surface of the operating rotary table in the above embodiment, the cam surface may be formed across the entire height of the outer peripheral surface of the operating rotary table. In this case, lengths of the cam follower and the retreat groove may be prolonged accordingly.

Although the retreat groove is formed in the base in the above embodiment, the retreat groove may not be provided. In this case, the cam surface may be designed to be recessed inward more than the above embodiment and/or the distance between the outer peripheral surface of the operating rotary table and the surface facing the outer peripheral surface of the base may be increased.

Although the urging spring, a left end of which bears against the support rib of the fixed barrier and a right end of which bears against the support plate of the movable barrier, is used as the presser in the above embodiment, a tensile spring, a left end of which is connected to the support plate (or a spring connector) of the movable barrier and a right end of which is connected to a spring connector of the fixed barrier. In this case, the tensile spring also functions to apply the rightward force to the movable barrier. Further, the presser may also take forms such as an elastic band, a disk spring, a magnet and the like, as long as the presser can provide a force to press the cam follower against the outer peripheral surface of the operating rotary table.

Although the presser is used in the above embodiment, the presser may not be provided. In this case, the requirements of the safety regulations can still be guaranteed while the angular cutting is being performed. When the vertical cutting is performed by the miter saw, since a case in which the saw blade interferes with the movable barrier does not exist, the user can adjust the movable barrier at any time without remembering to adjust it previously.

Although the step-like mounting columns are used in the above embodiment, step-free mounting columns may be provided. In this case, the mounting screws to be fitted into the mounting columns may be modified into step-like mounting screws. Further, the number of the mounting columns (and the mounting screws, the long holes and the washers corresponding to the mounting columns) is not limited to two, and may be one or more than two.

Although the movable connection between the movable barrier and the fixed barrier is achieved by the mounting columns, the mounting screws, the long holes and the like, the movable connection between the movable barrier and the fixed barrier is not limited thereto. For example, a slider-chute type connection may be used between the movable barrier and the fixed barrier. In this case, for example, the fixed barrier may be provided with a chute which cooperates with the movable barrier and extends in the longitudinal direction of the fixed barrier.

For the purpose of explanation and description, some exemplary embodiments of the present utility model have been given hereinabove. However, the foregoing description is not intended to be exhaustive or to restrict the present utility model to precise forms disclosed herein. Obviously, those skilled in the art can make various alterations and modifications. For example, individual features can be arbitrarily combined, substituted or omitted within the spirit and scope of the present utility model. Therefore, the scope of the present utility model should be defined only by the attached claims and the equivalent contents thereof.

Claims

A movable barrier positioning mechanism used in a miter saw, comprising:

a base；

an operating rotary table which is mounted to the base and is swingingly rotatable with respect to the base in a horizontal plane, a kerf being provided in an upper surface of the operating rotary table；

a fixed barrier which is fixedly mounted to the base, a longitudinal direction of the fixed barrier being in the horizontal plane and perpendicular to a direction along which the kerf extends when the miter saw is in a vertical cutting position, the fixed barrier having a workpiece positioning surface perpendicular to the horizontal plane； and

a movable barrier which is mounted into the fixed barrier in such a manner as to be movable in the longitudinal direction of the fixed barrier,

characterized in that a cam surface is formed on an outer peripheral surface of the operating rotary table,

a cam follower cooperating with the cam surface is provided on one end of the movable barrier far from the kerf, and

when the operating rotary table is swingingly rotated, the cam follower is guided by the cam surface so that the movable barrier is moved in the longitudinal direction of the fixed barrier.
The movable barrier positioning mechanism according to claim 1, characterized in that

the movable barrier positioning mechanism further includes a presser which is used to apply a force pressing the cam follower against the outer peripheral surface of the operating rotary table to the movable barrier.
The movable barrier positioning mechanism according to claim 2, characterized in that

the presser is a spring provided between the movable barrier and the fixed barrier.
The movable barrier positioning mechanism according to any one of claims 1 to 3, characterized in that

the cam surface is constituted by two convex segments and one concave segment smoothly connecting the two convex segments together.
The movable barrier positioning mechanism according to any one of claims 1 to 3, characterized in that

mounting columns with threaded holes are provided in the fixed barrier, the movable barrier is provided with long holes extending in the longitudinal direction of the fixed barrier at positions corresponding to the mounting columns, and the movable barrier is mounted to the mounting columns via mounting screws penetrating through the long holes.
The movable barrier positioning mechanism according to any one of claims 1 to 3, characterized in that

a retreat groove is formed at a position corresponding to the cam follower in a surface of the base facing the outer peripheral surface of the operating rotary table, and when the operating rotary table is swingingly rotated from the vertical cutting position, at least a part of the cam follower enters into the retreat groove in a direction away from the kerf.
The movable barrier positioning mechanism according to any one of claims 1 to 3, characterized in that

the cam follower is a cylindrical cam driven pin provided at the bottom of the movable barrier.
The movable barrier positioning mechanism according to any one of claims 1 to 3, characterized in that

the cam follower is provided at the bottom of the movable barrier and constituted by a fixed shaft and a rotary sleeve nested on the fixed shaft, and the rotary sleeve is rotated when the cam follower is guided by the cam surface.
The movable barrier positioning mechanism according to any one of claims 1 to 3, characterized in that

the movable barrier has a workpiece positioning surface, and the workpiece positioning surface of the movable barrier is coplanar with the workpiece positioning surface of the fixed barrier.
The movable barrier positioning mechanism according to any one of claims 1 to 3, characterized in that

the number of the movable barrier is two, the two movable barriers are provided on both sides of the kerf, and two cam surfaces respectively corresponding to cam followers of the two movable barriers are formed on the outer peripheral surface of the operating rotary table.
A miter saw, characterized in that

the miter saw comprises the movable barrier positioning mechanism according to any one of claims 1 to 10.