Modularized withdrawable circuit breaker

Abstract

A padlock plate, an unlocking button, an insertion through hole and an indication rotating rod are arranged on the front face of a circuit breaker shell from top to bottom in an embedded mode, the interior of the insertion through hole is connected with a transmission coupling, and a locking clamping frame is arranged on the outer side of the transmission coupling; the other end of the rotating coupler is connected with the transmission screw through a spring bearing seat, the indication linkage plate is arranged on the outer side of the transmission screw in a threaded connection mode, the torsion head is movably arranged at the upper end of the indication linkage plate through a shaft pin, and the indication rotating rod is arranged in the middle of the displacement transmission device in a penetrating mode. The three positions of connection, test and isolation are automatically locked, damage caused by misoperation is avoided, a padlock can be used for locking the position, the draw-out device is installed on the side of the circuit breaker body, A / S replacement is convenient, and the situation that a draw-out device in the market is designed at the bottom of the frame side, A / S replacement is convenient, and a frame unit needs to be detached from a power distribution cabinet is avoided.

Description

Technical Field

[0001] This article belongs to the technical field of modular circuit breakers, and specifically relates to a modular withdrawable circuit breaker. Background Art

[0002] Circuit breakers are important control and protection devices in power systems. They generally require energy storage mechanisms, closing mechanisms, and opening mechanisms. These mechanisms are installed in different locations on the circuit breaker chassis and cooperate with each other through a large number of transmission components to form an interconnected circuit breaker system. This increases the size of the circuit breaker and the chassis requires a larger space. In addition, the overall structure is very complex, which is not conducive to installation and subsequent maintenance, and has a short service life.

[0003] Therefore, in order to adapt to more installation environments and optimize the overall structure, most modular circuit breakers are installed in a withdrawable manner, and are rocked in and out by a rocker to complete the installation of the circuit breaker. Although this form can easily connect it to the chassis of the switch cabinet, it is still difficult to directly observe the installation status, resulting in excessive force from the wrench during assembly, causing damage to the connection points or clips, thereby affecting the installation of the circuit breaker. Utility Model Content

[0004] In order to solve the above problems, this paper proposes a modular withdrawable circuit breaker, wherein a rectangular circuit breaker housing is provided on the outside of the circuit breaker, and a twist head is movably extended inside the circuit breaker housing. The front of the circuit breaker housing is embedded with a padlock plate, an unlocking button, a plug-in hole and an indicator rotating rod from top to bottom. The inside of the plug-in hole is connected to the transmission coupling, and the outside of the transmission coupling is provided with a locking bracket. The other end of the rotating coupling is connected to the transmission screw through a spring bearing seat, and the outer side of the transmission screw is threadedly connected with an indicator linkage plate. The upper end shaft pin of the indicator linkage plate is movably provided with a twist head, and the lower end of the indicator linkage plate is connected to the displacement transmission device. The middle part of the displacement transmission device is provided with an indicator rotating rod. The front end surface of the indicator rotating rod is protruding and arranged on the front side of the circuit breaker housing. The outer side of the front end of the indicator rotating rod is provided with a rotating convex ring. A linkage locking hook is provided on the upper horizontal center axis of the ring, and the linkage locking hook is embedded in the bottom of the locking card frame. One end of the locking card frame protrudes above and is fixedly connected to the unlocking button. A push slider is provided on the outside of the surface of one end of the locking card frame, and the other end surface of the locking card frame is connected to the spring of the spring bearing seat. The bottom of the push slider is outsourced and provided with the outer side of the end of the rotating coupling. The upper end of the push slider is provided in the limit slot at the bottom of the padlock plate. It can be assembled modularly and automatically locked in the connection / test / isolation positions to avoid damage due to improper operation. The padlock can be used to lock the position. The new withdrawal device is installed on the side of the circuit breaker body. When rocking in and out, the position of this part is clearly visible. The new withdrawal device is installed on the side of the circuit breaker body, which is convenient for A / S replacement. It will not be designed at the bottom of the frame side like the withdrawal device on the market. It is convenient for A / S replacement, and the frame unit needs to be removed from the distribution cabinet.

[0005] The circuit breaker housing is in the shape of a long rectangular shell. The rear ends of the two side surfaces of the circuit breaker housing are longitudinally provided with a plurality of indexing guide grooves. The rear end of the upper surface of the circuit breaker housing is provided with a lead-out groove. The indexing guide grooves on both sides are equidistant and parallel to each other, and the length of the indexing guide grooves on both sides decreases from top to bottom. The inner side of the indexing guide groove is connected to the indicator linkage plate through a guide column. The inner side of the lead-out groove is provided with a twist head for flipping and leading out. By providing the indexing guide grooves on the outer surface of the circuit breaker housing, not only can the indicator linkage plate be conveniently displaced in a linked manner, but the displacement of the indicator linkage plate can also be conveniently observed from the side of the circuit breaker housing. The left and right clamps and fix the internal parts, and are bent at one point on each side for installing the extraction device.

[0006] The padlock plate is in the shape of a rectangular flat plate, and a padlock slot is vertically provided on the front end surface of the padlock plate. A recovery spring is embedded in the interior of the padlock plate, and a limit slot is provided at the bottom of the padlock plate. Limit convex edges are provided on both sides of the outer side of the padlock slot of the padlock plate. The shape of the push slider is a rectangular plate, and a folded corner fixing hook is provided on the upper end of the push slider. The middle upper side of the push slider is penetrated by the outer side of the connecting pressing rod, and the middle lower side of the push slider is penetrated by a handle socket. The diameter of the handle socket is smaller than the middle diameter of the rotating handle. The padlock can be hung on the front of the circuit breaker housing through the padlock plate, so that the movable slider is limited to prevent movement, and the movable slider can limit the insertion of the rotating handle, thereby achieving physical locking of the circuit breaker.

[0007] The locking bracket is in the shape of a directional frame structure. A connection pressing rod is protruding from the upper front surface of the locking bracket. A coupling assembly hole is provided transversely through the lower side of the locking bracket. An unlocking button is fixedly provided at the front end of the connection pressing rod. A transmission coupling is embedded in the coupling assembly hole. An outward pull-out slot is provided on the bottom surface of the locking bracket. A transversely protruding assembly post is provided above the rear end of the locking bracket. A linkage locking hook is longitudinally provided on the inner side of the outward pull-out slot. The middle portion of the linkage locking hook is axially arranged on both sides of the inner side of the circuit breaker housing. The locking bracket can extend the linkage locking hook from the outer side of the circuit breaker housing to lock the circuit breaker and limit the number of rotations of the rotary handle, ensuring that the circuit breaker can be automatically locked in the three positions of connection / test / isolation. The connection pressing rod can be pressed and displaced from the front outer side of the circuit breaker housing to achieve displacement of the locking bracket. The inward displacement of the locking bracket can rotate the rotary handle to drive subsequent rotation.

[0008] The spring bearing seat is a fixed bearing seat. The front end surface of the spring bearing seat is convexly provided with a return spring. The front end of the spring bearing seat is plugged into and connected to the rear end of the rotating coupling. The rear end of the spring bearing seat is plugged into and connected to the front end of the rotating screw. The outer side of the spring bearing seat is embedded and fixed inside the parallel positioning plate. The outer end of the return spring is connected to the end face of the locking bracket. The spring bearing seat can not only assist the rotation of the rotating coupling, but also realize the self-resetting effect of the locking bracket through the return spring.

[0009] The indicating linkage plate is in the shape of a rectangular block plate, and a stepping thread is provided through the center of the bottom of the indicating linkage plate, and a displacement transmission device is fixedly connected at the lower end of the indicating linkage plate. Guide columns are provided on both side surfaces of the indicating linkage plate, and a displacement groove is vertically provided through the rear end of the indicating linkage plate. The two side surfaces of the displacement groove are aligned and through-type with a discharge groove, and the inner side of the discharge groove is connected to the twist head through a guide column. The shape of the twist head is a circular ear plate, and the bottom of the twist head is movably connected to the discharge groove through a guide column, and a hexagonal connecting hole is provided through the center surface of the twist head. The indicating linkage plate can not only perform linkage displacement by rotating the screw, but also perform stable indexing displacement through the guide column, and in the process of displacement, the twist head can also be extended through the discharge groove, thereby realizing the rotation control of the twist head when the handle is turned.

[0010] The indicator rotating rod is a cylindrical straight rod, and the front end surface of the indicator rotating rod is provided with an indicator arrow, the front end outer surface of the indicator rotating rod is provided with a rotating convex ring in an annular manner, and the rear end outer surface of the indicator rotating rod is provided with a guide screw in an annular threaded manner. The guide screw is plugged into the displacement transmission, and the middle part of the indicator rotating rod is supported by the parallel positioning plate. The indicator rotating rod can be controlled by the linkage of the displacement transmission, so that the displacement of the displacement transmission drives the indicator rotating rod to perform auxiliary rotation. After the indicator rotating rod is rotated to a certain angle, the linkage locking hook is pushed upward by the rotating convex ring, thereby achieving the release of the return limit of the locking card frame, so that the locking card frame can automatically return to the center.

[0011] The shape of the rotating handle is a cylindrical plug-in handle. The front end of the rotating handle is provided with an external slot, and the rear end of the rotating handle is sequentially expanded to provide a segmented step shaft. The diameter of the minor step of the segmented step shaft of the rotating handle is the same as the diameter of the handle socket. By inserting the rotating handle, the rotating coupling can be easily rotated from the inside, and the segmented step shaft with the step can limit the insertion of the rotating handle by pushing the slider, thereby ensuring the mechanical locking of the circuit breaker.

[0012] Beneficial effects:

[0013] It can be assembled in modules, and the three positions of connection / test / isolation are automatically locked to avoid damage due to improper operation. The position can be locked with a padlock. The new withdrawable device is installed on the side of the circuit breaker body. When it is shaken in and out, the position of this part is clearly visible. The new withdrawable device is installed on the side of the circuit breaker body, which is convenient for A / S replacement. Unlike the withdrawable device on the market that is designed at the bottom of the frame side, it is convenient for A / S replacement, and the frame unit needs to be removed from the distribution cabinet.

[0014] By setting a graduated guide groove on the outer surface of the circuit breaker housing, not only can the linkage plate be easily moved, but the displacement of the linkage plate can also be easily observed from the side of the circuit breaker housing. The left and right clamps are used to fix the internal parts and bend one part on each side for installing the withdrawal device.

[0015] A padlock can be hung on the front of the circuit breaker housing through the padlock plate, so that the movable slider is limited to prevent movement, and the movable slider can limit the insertion of the rotating handle, thereby physically locking the circuit breaker.

[0016] The locking bracket can extend a linkage locking hook from the outside of the circuit breaker housing to lock the circuit breaker. It can also limit the number of turns of the rotary handle to ensure that the circuit breaker can be automatically locked in the three positions of connection / test / isolation. The connection pressing rod can be pressed and displaced from the front outside of the circuit breaker housing to achieve the displacement of the locking bracket. The inward displacement of the locking bracket can enable the rotary handle to be rotated and drive the subsequent rotation effect.

[0017] The spring bearing seat can not only assist the rotation of the rotating coupling, but also realize the self-resetting effect of the locking bracket through the return spring.

[0018] The indicating linkage plate can not only be displaced in linkage by rotating the screw, but also be displaced stably by indexing through the guide column. During the displacement process, it can also be extended by twisting the head through the discharge chute, thereby realizing the rotation control of the twist head when turning the handle.

[0019] By inserting the rotating handle, the rotating coupling can be easily rotated from the inside, and the step is a segmented step shaft that pushes the slider to limit the insertion of the rotating handle, thereby ensuring the mechanical locking of the circuit breaker. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a schematic diagram of the internal section of a modular withdrawable circuit breaker;

[0021] Figure 2 It is a side view of a modular withdrawable circuit breaker;

[0022] Figure 3 This is a front view of a modular withdrawable circuit breaker;

[0023] In the figure; 1. Circuit breaker housing, 2. Padlock plate, 3. Push slider, 4. Unlock button, 5. Locking bracket, 6. Rotating coupling, 7. Parallel positioning plate, 8. Spring bearing seat, 9. Rotating screw, 10. Indicating linkage plate, 11. Twist head, 12. Displacement actuator, 13. Indicating rotating rod, 14. Rotating handle, 15. Linkage locking hook. DETAILED DESCRIPTION

[0024] In order to deepen the understanding of the present invention, the present invention will be further described in detail below with reference to embodiments and drawings. The embodiments are only used to explain the present invention and do not constitute a limitation on the scope of protection of the present invention.

[0025] Circuit breaker housing 1, padlock plate 2, push slider 3, unlocking button 4, locking bracket 5, rotating coupling 6, parallel positioning plate 7, spring bearing seat 8, rotating screw 9, indicating linkage plate 10, twist head 11, displacement transmission 12, indicating rotating rod 13, rotating handle 14, linkage locking hook 15.

[0026] like Figure 1 、 2 , 3 shown;

[0027] A modular withdrawable circuit breaker, a rectangular circuit breaker housing 1 is provided on the outside of the circuit breaker, a twist head 11 is provided inside the circuit breaker housing 1, and a padlock plate 2, an unlocking button 4, a plug-in hole and an indicator rotating rod 13 are embedded from top to bottom on the front of the circuit breaker housing 1. The inside of the plug-in hole is connected to the transmission coupling, and the outside of the transmission coupling is provided with a locking bracket 5. The other end of the rotating coupling 6 is connected to the transmission screw through a spring bearing seat 8. The outside of the transmission screw is threadedly connected with an indicator linkage plate 10. The upper end of the indicator linkage plate 10 is movable with a twist head 11, and the lower end of the indicator linkage plate 10 is connected to the displacement transmission 12. The middle of the displacement transmission 12 An indicator rotating rod 13 is provided through the circuit breaker housing 1, and the front end surface of the indicator rotating rod 13 is protrudingly provided on the front side of the circuit breaker housing 1. A rotating convex ring is provided in an annular manner on the outer side of the front end of the indicator rotating rod 13. A linkage locking hook 15 is provided on the upper side of the rotating convex ring so as to rotate horizontally around the central axis. The linkage locking hook 15 is embedded in the bottom of the locking card frame 5. The upper side of one end of the locking card frame 5 is protruding and fixedly connected to the unlocking button 4. A push slider 3 is provided on the outer side of one end surface of the locking card frame 5. The other end surface of the locking card frame 5 is connected to the spring of the spring bearing seat 8. The bottom of the push slider 3 is outsourced to the outer side of the end of the rotating coupling 6. The upper end of the push slider 3 is provided in the limit slot at the bottom of the padlock plate 2. The shape of the circuit breaker housing 1 is a long rectangular shell, and the rear ends of the two side surfaces of the circuit breaker housing 1 are longitudinally provided with a plurality of indexing guide grooves, and the rear end of the upper surface of the circuit breaker housing 1 is provided with a lead-out groove, and the indexing guide grooves on both sides are equidistant and parallel to each other, and the length of the indexing guide grooves on both sides decreases from top to bottom. The inner side of the indexing guide groove is connected to the indicator linkage plate 10 through a guide column, and the inner side of the lead-out groove is flipped and led out with a twist head 11, and the padlock plate 2 is shaped like a rectangular flat plate, and the front end surface of the padlock plate 2 is vertically provided with a padlock slot hole, and the interior of the padlock plate 2 is embedded with a recovery spring, and the bottom of the padlock plate 2 is provided with a limit card slot, and the outer sides of the padlock slot of the padlock plate 2 are provided with limit convex edges on both sides, and the shape of the locking card frame 5 is a directional frame structure. A connecting pressing rod is protruding above the front end surface of the locking card frame 5, and a coupling assembly hole is provided horizontally through the bottom of the locking card frame 5. The front end of the connecting pressing rod is fixedly provided with an unlocking button 4, and a transmission coupling is embedded in the coupling assembly hole. The bottom surface of the locking card frame 5 is provided with an external pull-out groove, and an assembly card column is protruding horizontally above the rear end of the locking card frame 5. The inner side of the external pull-out groove is longitudinally provided with a linkage locking hook 15. The middle part of the linkage locking hook 15 is axially arranged on both sides of the interior of the circuit breaker housing 1. The spring bearing seat 8 is a fixed bearing seat, and the front end surface of the spring bearing seat 8 is protruding with a return spring. The front end of the spring bearing seat 8 is plug-connected to the rear end of the rotating coupling 6.The rear end of the spring bearing seat 8 is plugged into the front end of the rotating screw 9, and the outer side of the spring bearing seat 8 is embedded and fixed in the parallel positioning plate 7. The outer end of the return spring is connected to the end face of the locking bracket 5. The shape of the indicating linkage plate 10 is a rectangular block plate, and the bottom center of the indicating linkage plate 10 is penetrated by a stepping thread, and the lower end of the indicating linkage plate 10 is fixedly connected with a displacement transmission device 12. The surfaces of both sides of the indicating linkage plate 10 are provided with guide columns, and the rear end of the indicating linkage plate 10 is vertically penetrated by a displacement groove, and the two side surfaces of the displacement groove are aligned and penetrated with a discharge groove, and the inner side of the discharge groove is connected to the twist head 11 through a guide column. The shape of the twist head 11 is a circular ear plate, and the bottom of the twist head 11 is movably connected to the discharge groove through a guide column. The center surface of the twist head 11 is penetrated by a hexagonal connecting hole, and the indicating rotating rod 13 is a cylindrical straight rod. The front end surface of the rotating rod 13 is provided with an indicator arrow, the outer surface of the front end of the indicating rotating rod 13 is provided with a rotating convex ring in an annular manner, and the outer surface of the rear end of the indicating rotating rod 13 is provided with a guide screw in an annular threaded manner. The guide screw is plugged into the displacement transmission device 12, and the middle part of the indicating rotating rod 13 is supported and connected with the parallel positioning plate 7. The push slider 3 is in the shape of a rectangular plate, and the upper end of the push slider 3 is provided with a folded corner fixing hook. The upper side of the middle part of the push slider 3 is provided with a handle socket that penetrates the outer side of the connecting pressing rod, and the lower side of the middle part of the push slider 3 is provided with a handle socket. The diameter of the handle socket is smaller than the middle diameter of the rotating handle 14. The rotating handle 14 is in the shape of a cylindrical plug-in handle. The front end of the rotating handle 14 is provided with an external slot. The rear end of the rotating handle 14 is sequentially expanded with a segmented step shaft. The diameter of the small-diameter step of the segmented step shaft of the rotating handle 14 is the same as the diameter of the handle socket.

[0028] Implementation examples;

[0029] The circuit breaker housing 1 can be assembled in a modular manner, and the three positions of connection / test / isolation are automatically locked to avoid damage caused by improper operation. The padlock plate 2 can be locked in position using a padlock.

[0030] The new drawout mechanism is installed on the side of the circuit breaker body, and the position of the main unit is clearly visible when swinging in and out. Unlike the drawout mechanism designed on the market, which is designed at the bottom of the frame side and is blocked by the body when swinging in and out, the position indication is not visible.

[0031] The new drawout unit is installed on the side of the circuit breaker body, making it easy to replace the A / S. The drawout unit can be replaced by simply pulling out the body. Unlike the current market where the drawout unit is designed at the bottom of the frame side, it is not easy to replace the A / S without removing the frame unit from the distribution cabinet.

[0032] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A modular withdrawable circuit breaker, wherein a rectangular circuit breaker housing is provided on the outside of the circuit breaker, and a twist head is provided inside the circuit breaker housing in a movable and extendable manner, characterized in that: The front of the circuit breaker housing is embedded with a padlock plate, an unlocking button, a plug-in through-hole and an indicator rotating rod from top to bottom. The interior of the plug-in through-hole is connected to the transmission coupling. The outer side of the transmission coupling is provided with a locking bracket. The other end of the rotating coupling is connected to the transmission screw through a spring bearing seat. The outer side of the transmission screw is threadedly connected with an indicator linkage plate. The upper end of the indicator linkage plate is movably provided with a torsion head. The lower end of the indicator linkage plate is connected to the displacement transmission. The middle of the displacement transmission is provided with an indicator rotating rod. The front end of the indicator rotating rod The protruding surface is provided on the front side of the circuit breaker housing, and a rotating convex ring is provided in an annular manner on the outer side of the front end of the indicating rotating rod. A linkage locking hook is provided above the rotating convex ring and rotates horizontally along the central axis. The linkage locking hook is embedded in the bottom of the locking card frame. The upper part of one end of the locking card frame is fixedly connected to the unlocking button. A push slider is provided on the outer side of the surface of one end of the locking card frame. The other end surface of the locking card frame is connected to the spring of the spring bearing seat. The bottom of the push slider is outwardly provided with the outer side of the end of the rotating coupling, and the upper end of the push slider is provided in the limit slot at the bottom of the padlock plate.

2. A modular withdrawable circuit breaker according to claim 1, characterized in that: The circuit breaker housing is in the shape of a long rectangular shell. The rear ends of the two side surfaces of the circuit breaker housing are longitudinally provided with a plurality of indexing guide grooves. The rear end of the upper surface of the circuit breaker housing is provided with an outlet groove. The indexing guide grooves on both sides are equidistant and parallel to each other. The length of the indexing guide grooves on both sides decreases from top to bottom. The inner side of the indexing guide groove is connected to the indicator linkage plate through a guide column. The inner side of the outlet groove is provided with a twist head for flipping and leading out.

3. The modular withdrawable circuit breaker according to claim 1, characterized in that: The padlock plate is in the shape of a rectangular flat plate, a padlock slot is vertically provided on the front end surface of the padlock plate, a recovery spring is embedded inside the padlock plate, a limit slot is provided at the bottom of the padlock plate, and limit convex edges are provided on both sides of the outer side of the padlock slot of the padlock plate.

4. The modular withdrawable circuit breaker according to claim 1, characterized in that: The locking bracket is in the shape of a directional frame structure, a connecting pressing rod is protruding above the front end surface of the locking bracket, a coupling assembly hole is horizontally penetrated below the locking bracket, an unlocking button is fixed at the front end of the connecting pressing rod, a transmission coupling is embedded in the coupling assembly hole, an outward pull-out groove is provided on the bottom surface of the locking bracket, an assembly column is horizontally protruding above the rear end of the locking bracket, a linkage locking hook is longitudinally provided on the inner side of the outward pull-out groove, and the middle part of the linkage locking hook is axially arranged on both sides of the inner side of the circuit breaker housing.

5. The modular withdrawable circuit breaker according to claim 1, characterized in that: The spring bearing seat is a fixed bearing seat, and a return spring is protruding from the front end surface of the spring bearing seat. The front end of the spring bearing seat is plugged into and connected to the rear end of the rotating coupling, and the rear end of the spring bearing seat is plugged into and connected to the front end of the rotating screw. The outer side of the spring bearing seat is embedded and fixed inside the parallel positioning plate, and the outer end of the return spring is connected to the end face of the locking bracket.

6. The modular withdrawable circuit breaker according to claim 1, characterized in that: The shape of the indicating linkage plate is a rectangular block plate, the bottom center of the indicating linkage plate is penetrated by a stepping thread, the lower end of the indicating linkage plate is fixedly connected with a displacement transmission device, both side surfaces of the indicating linkage plate are provided with guide columns, the rear end of the indicating linkage plate is vertically penetrated by a displacement groove, the two side surfaces of the displacement groove are aligned and penetrated by a discharge groove, the inner side of the discharge groove is connected to the twist head through a guide column, the shape of the twist head is a circular ear plate, the bottom of the twist head is movably connected to the discharge groove through a guide column, and the center surface of the twist head is penetrated by a hexagonal connecting hole.

7. The modular withdrawable circuit breaker according to claim 1, characterized in that: The indicating rotating rod is a cylindrical straight rod, the front end surface of the indicating rotating rod is provided with an indicating arrow, the front end outer surface of the indicating rotating rod is provided with a rotating convex ring in an annular manner, and the rear end outer surface of the indicating rotating rod is provided with a guide screw in an annular threaded manner. The guide screw is plugged into the displacement transmission, and the middle part of the indicating rotating rod is supported and connected to the parallel positioning plate.

8. The modular withdrawable circuit breaker according to claim 4, characterized in that: The push slider is in the shape of a rectangular plate, and a folded corner fixing hook is provided at the upper end of the push slider. The upper middle side of the push slider is penetrated by the outer side of the connecting pressing rod, and the lower middle side of the push slider is penetrated by a handle socket. The diameter of the handle socket is smaller than the middle diameter of the rotating handle.

9. The modular withdrawable circuit breaker according to claim 8, characterized in that: The rotating handle is shaped like a cylindrical plug-in handle, with an external slot provided at the front end of the rotating handle and a segmented step shaft which is sequentially expanded at the rear end of the rotating handle. The diameter of the minor step of the segmented step shaft of the rotating handle is the same as the diameter of the handle socket.

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