Change-over switch with high breaking capacity and high switching-on capacity

Abstract

The invention discloses a change-over switch with high breaking capacity and high connection capacity, which comprises a contact mechanism and a driving piece which are arranged in a shell, the contact mechanism comprises two groups of moving contact assemblies and two groups of static contact assemblies which are correspondingly matched, and the driving piece comprises two driving cams which coaxially rotate and are arranged in a staggered manner; the two groups of moving contact assemblies move towards the static contact assembly through the elastic piece and are linked with the double cams, and the two driving cams apply uniform and enough thrust to the two groups of moving contact assemblies through respective high cam sections so as to overcome the pressure of the elastic piece to realize forced breaking and avoid the situation that the contact cannot be broken when fusion welding adhesion occurs. The falling type structure of the low cam section is matched with the release rhythm of the elastic piece, and the movable contact assembly is pushed to perform quick switching-on action through the released energy of the elastic piece, so that the switching-on speed of switching-on is ensured; according to the design, the three-station switching structure is simplified, the cost and the operation complexity are reduced, rapid and reliable connection and disconnection are realized, the electrical performance and the safety of the switch are improved, and the service life of the switch is prolonged.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of low-voltage electrical apparatus, in particular to a transfer switch with high breaking and high making capacity. BACKGROUND

[0002] As a key electrical component, the transfer switch is widely used in industrial and civil power distribution systems to realize reliable switching of the load between the main power supply and the standby power supply, and to ensure the continuity and safety of power supply. In the power switching process of the traditional transfer switch, the load is directly switched between the main power supply and the standby power supply, lacking an intermediate transition state, which is easy to cause impact on the load equipment due to current mutation, affecting the service life of the equipment and even causing failure.

[0003] A transfer switch structure with an intermediate disconnection gear has appeared in the prior art. For example, Chinese patent document CN115424900A discloses a transfer switch including a housing, a shifting element and a conduction assembly. The housing is provided with a main wiring contact and a secondary wiring contact, and corresponding load contacts (the main wiring contact and the secondary wiring contact are collectively referred to as static contacts). The conduction assembly includes a connecting element, a spring and a first contact group and a second contact group spaced apart on the connecting element. When the shifting element rotates, it drives the conduction assembly to move, thereby alternately realizing the contact or separation of the two contact groups and the static contacts, to realize the switching of the three gears of the main power supply on-off-backup power supply on. Although this transfer switch can realize three-gear switching control, from the switch structure, it can be seen that it still has the following problems: Firstly, in the closing process, the closing of the contacts of the first contact group depends on the rotation of the shifting element to drive the connecting element to move down, so that the contacts contact the static contacts. This process is a gradual mechanical transmission, which causes the closing speed of the contacts to be affected by the speed of the operator rotating the handle, and it is impossible to realize fast and reliable connection. Slow closing is easy to cause the duration of electric arc to be prolonged, which aggravates the electric wear of the contacts, affecting the electrical life and making capacity of the switch. Secondly, in the breaking process, the separation of the moving contacts of the first contact group depends on the elastic force of the spring to drive the connecting element to move, so as to realize the separation from the static contacts. However, when the contacts are welded and adhered due to large current or short circuit, the restoring force of the spring may be insufficient to overcome the adhesion force, so that the contacts cannot be separated in time and effectively. At this time, the handle can continue to rotate to the intermediate gear, but the actual circuit is not disconnected, causing false breaking, which seriously affects the breaking reliability and even misleads the operator's judgment, posing a safety hazard. In summary, the structural design of the existing transfer switch causes at least one group of contacts to not have the ability of fast connection and breaking of high-voltage circuit, which limits its application in occasions requiring high breaking and high making capacity. SUMMARY

[0004] Therefore, the technical problem to be solved by the present application is to overcome the problem that the structure design of the existing transfer switch results in a group of contacts not having the ability to quickly connect and disconnect high-voltage circuits, which aggravates the electrical wear of the contacts and affects the electrical life and connection capacity of the switch.

[0005] To solve the above problems, the present application provides a transfer switch with high breaking and high connection capacity, comprising a shell, a contact mechanism arranged in the shell, and a driving member, wherein the contact mechanism comprises two groups of moving contact assemblies arranged in the shell in the same direction, and two groups of static contact assemblies corresponding to the two groups of moving contact assemblies for contact or disconnection; the driving member has a first position for driving the first group of moving contact assemblies and the static contact assemblies to connect a first circuit, a second position for driving the second group of moving contact assemblies and the static contact assemblies to connect a second circuit, and an initial position for driving the two groups of moving contact assemblies and the two groups of static contact assemblies to disconnect the corresponding circuits. The driving member comprises two driving cams arranged coaxially and staggered, the two groups of moving contact assemblies are connected to the two driving cams one by one through elastic members to form a linkage, and the two driving cams drive the two groups of moving contact assemblies to alternately connect the two groups of static contact assemblies when the driving member switches between the first position and the second position; and the two driving cams drive the two groups of moving contact assemblies to overcome the pressure of the elastic members and disconnect the two groups of static contact assemblies when the driving member is in the initial position.

[0006] In the above-mentioned transfer switch, the two driving cams are provided with high cam segments and low cam segments with smooth and connected outer peripheries to form a cam outer periphery with a drop connection, and the low cam segments of the two driving cams are arranged on one side of the high cam segments of the two driving cams, and the two driving cams drive the two groups of moving contact assemblies to alternately move through the cooperation of the high cam segments and the low cam segments.

[0007] In the above-mentioned transfer switch, the two groups of moving contact assemblies are provided with two contact shafts in sliding contact with the outer peripheries of the two driving cams, the axes of the contact shafts are parallel to the rotation axis of the driving member, the driving member drives the two contact shafts to cooperate with the high cam segments of the two driving cams when the driving member is in the initial position, and the driving member drives one contact shaft to cooperate with the high cam segment of one driving cam and drives the other contact shaft to cooperate with the low cam segment of the other driving cam when the driving member switches from the initial position to the first position or the second position.

[0008] In the above-mentioned transfer switch, the driving member is a double cam structure arranged in the shell through the same rotation axis of the two driving cams, the cam outer peripheries of the two driving cams are arranged in a symmetrical structure, and the two driving cams are arranged at a preset angle along the rotation axis.

[0009] In the above-mentioned change-over switch, the two driving cams are divided into coaxially linked first and second cams, the high cam section includes a first circular-arc protrusion arranged on the outer periphery of the first cam and a second circular-arc protrusion arranged on the outer periphery of the second cam; the low cam section includes a first speed sliding part smoothly connected with the first circular-arc protrusion and a second speed sliding part smoothly connected with the second circular-arc protrusion, the first circular-arc protrusion and the second circular-arc protrusion partially overlap in the circumferential direction, and the first and second speed sliding parts are arranged in the circumferential direction in a left-right staggered manner.

[0010] In the above-mentioned change-over switch, the distance from the outer peripheral contour surface of the first circular-arc protrusion to the rotation axis is the same as the distance from the outer peripheral contour surface of the second circular-arc protrusion to the rotation axis, and when any one of the contact shafts rolls along the high cam section of the driving cam to the low cam section, the corresponding moving contact assembly is quickly moved to close to the stationary contact assembly under the action of the spring member; when any one of the contact shafts rolls from the low cam section of the driving cam to the high cam section, the moving contact assembly is moved away from the stationary contact assembly against the force of the spring member.

[0011] In the above-mentioned change-over switch, the first cam includes first and second clamping openings arranged at intervals on the first circular-arc protrusion, the first and second clamping openings have the same linear distance to the rotation axis and are respectively matched with the contact shaft of one group of moving contact assemblies; the second cam includes third and fourth clamping openings arranged at intervals on the second circular-arc protrusion, the third and fourth clamping openings have the same linear distance to the rotation axis and are respectively matched with the contact shaft of the other group of moving contact assemblies; the first and third clamping openings are arranged in axial alignment, and the second and fourth clamping openings are arranged in circumferential stagger; when the two contact shafts are clamped in the first and third clamping openings respectively, the driving member is locked in the initial position; when one of the contact shafts is clamped in the second or fourth clamping opening, the driving member is locked in the first or second position, and the other contact shaft is matched and connected to the first or second speed sliding part.

[0012] In the above-mentioned change-over switch, the two sets of movable contact assemblies are divided into a first movable contact assembly matched with the first cam and a second movable contact assembly matched with the second cam, the first movable contact assembly comprises a first movable contact frame movably arranged in the shell and a first movable contact bridge and a contact spring arranged on the first movable contact frame in connection, the second movable contact assembly comprises a second movable contact frame movably arranged in the shell and a second movable contact bridge and a contact spring arranged on the second movable contact frame in connection, the elastic member comprises two compression springs arranged at the bottom of the first movable contact frame and the second movable contact frame respectively, two contact shafts are arranged at the top of the first movable contact frame and the second movable contact frame respectively, and the first movable contact frame and the second movable contact frame have a movement tendency towards the first cam and the second cam under the action of the two compression springs, so that the contact shaft of the first movable contact frame is in contact with the outer peripheral contour of the first cam, and the contact shaft of the second movable contact frame is in contact with the outer peripheral contour of the second cam.

[0013] In the above-mentioned change-over switch, the first movable contact bridge and the second movable contact bridge are arranged in a staggered manner along the height direction of the two sets of movable contact assemblies, and the two movable contact bridges have movable contact heads arranged towards the same side, the two sets of static contact assemblies comprise a first static contact and a second static contact arranged opposite to each other and matched with the first movable contact bridge, and a third static contact and a fourth static contact arranged opposite to each other and matched with the second movable contact bridge, and the first static contact and the third static contact are in an integral structure connected and extended to the same incoming line end.

[0014] In the above-mentioned change-over switch, the driving member comprises a coaxial part integrally connecting the first cam and the second cam, the coaxial part is provided with an axle hole through which the rotating shaft passes, and the first cam and the second cam are distributed on the two sides of the coaxial part in a staggered manner along the circumference.

[0015] In the above-mentioned change-over switch, the shell is provided with a guide groove structure guiding the linear movement of the first movable contact frame and the second movable contact frame, the side of the first movable contact frame facing the second movable contact frame is provided with a set of limiting grooves extending in the movement direction of the first movable contact frame, and the side of the second movable contact frame facing the first movable contact frame is correspondingly provided with a set of limiting blocks slidingly connected in the set of limiting grooves.

[0016] Compared with the prior art, the technical scheme of the present application has the following advantages: 1.The transfer switch provided by the present application, wherein the driving member has a coaxial staggered double cam structure, two groups of moving contact assemblies are linked and matched with the double cam structure through elastic members, and the energy storage and release of the two groups of moving contact assemblies by the elastic members realize the alternate connection mechanism of the two groups of moving contact assemblies, two driving cams control the moving track of the two groups of moving contact assemblies by using their respective cam profiles, the elastic members provide driving force for the quick action of the two groups of moving contact assemblies, so that the connection and disconnection process no longer depends on the manual operation speed, ensuring the consistency and reliability of each operation, and the transfer switch adopting the technical solution realizes the mechanical interlocking type alternate connection of the two groups of moving contact assemblies by the linkage and matching design between the double cam structure, the two groups of moving contact assemblies and the elastic members, so that only one group of moving contact assemblies is connected and the other group is kept disconnected when the driving member switches between the first position and the second position, which prevents the short circuit risk of simultaneous connection of the main and standby power supply, meets the safety standards of the transfer switch, and only when the driving member switches to the initial position, the two groups of moving contact assemblies are forced to separate from the static contact assembly by the high cam section of the double cam to overcome the pressure of the elastic members, so as to keep the double disconnected state, which simplifies the three-position switching structure, reduces the cost and operation complexity, realizes the quick and reliable connection and disconnection, and improves the electrical performance, safety and service life of the switch.

[0017] 2.The transfer switch provided by the present application, wherein the two driving cams are designed in a high-low cam section structure with a drop type connection, and the low cam sections of the two driving cams are staggered on one side of the high cam sections, which has the advantages that the two driving cams push the corresponding contact shafts to the two groups of moving contact assemblies through the high cam sections to apply uniform and sufficient thrust, stably overcome the pressure of the elastic members to realize forced disconnection, avoid the situation that the contacts cannot be disconnected when they are slightly welded and stuck, and match the release rhythm of the elastic members by using the drop type structure of the low cam section, so that when the contact shaft slides along the low cam section, the elastic members are used to quickly push the moving contact assemblies to ensure the closing speed; when the driving member switches from the initial position to the first position or the second position, only the low cam section of one driving cam releases the elastic member, so that the corresponding group of moving contact assemblies realizes closing, and the high cam section of the other driving cam continuously presses the contact shaft of the other group of moving contact assemblies, so that the other group of moving contact assemblies remains in the open state, which structurally eliminates the possibility of simultaneous connection of the two groups of circuits, thereby forming a physical structure constraint that "one group closes and the other group must disconnect", realizing mechanical hard interlocking, and eliminating the short circuit risk.

[0018] 3. The transfer switch provided by the present application, two drive cams adopt coaxial linkage phase staggered design, which ensures that the first cam and the second cam have absolute synchronization relationship in rotation angle and timing, and directly determines the phase difference of the first speed sliding part and the second speed sliding part in the circumferential direction, the two drive cams build physical interlocking for the two groups of moving contact assemblies through staggered profile phase, and the structure is set, when the driving part rotates from the initial position to any on position, due to the staggered angle distribution of the two drive cams, for example, the first cam enters the low cam section to make the first moving contact assembly ready to connect first, and the second cam still maintains in the high cam section for a small angle, ensuring that the corresponding second moving contact assembly continues to remain disconnected, which mechanically implements the first disconnecting and then connecting logic, eliminates the risk of short circuit, and strengthens the forced disconnecting force of the switch and improves the disconnecting reliability.

[0019] 4. The transfer switch provided by the present application, two cams jointly constitute three explicit mechanical locking points through design of four clamping holes, which correspond to the initial position, the first position and the second position respectively, when the contact shaft falls into the corresponding clamping hole, the driving part is mechanically clamped and cannot move by itself, the combination structure design of the double cam and the multi-clamping hole integrates the state locking, safety interlocking and force balance functions, which ensures that the switch can stably stay at the preset station under any working condition, which prevents the change of switch position caused by vibration, impact or non-human operation, and ensures the stability of the running state, which forcibly realizes the first disconnecting and then connecting logic and absolutely prevents double power short circuit.

[0020] 5. The transfer switch provided by the present application, two independent compression springs are used as elastic members and provide a pushing force towards the cam for the first and second moving contact frames respectively, which makes the contact shaft arranged at the top of the two moving contact frames always close to the outer profile of the two drive cams, and uses the force of the compression spring to unidirectionally make the moving contact assembly tend to close, builds an efficient energy storage-release mechanism through cooperation of the two compression springs and the two moving contact frames, and improves the closing speed of the two groups of moving contact assemblies, which realizes the rapid closing of the transfer switch by any group of contacts, greatly shortens the arc duration time, and directly improves the switching capacity and electrical life of the switch; according to the disconnecting force of the transfer switch which is actively provided by the drive cam, the force of the compression spring and any contact adhesion force are directly overcome, and reliable and mechanical forced disconnecting is realized, and the present application considers rapid action and forced disconnecting by designing two groups of independent moving contact assemblies and cooperating with the double cam structure.

[0021] 6. The switch provided by the present application, the driving member connects the first cam and the second cam through the coaxial part to form an integrated rigid functional part. This ensures the relative phase angle between the two cams, and during the rotation of the driving member, the two cams move as a whole, and the timing relationship of the two sets of moving contact assemblies is not delayed or misaligned, ensuring the high reliability and consistency of the switching process, and the two cams adopt a central symmetric structure to optimize the mechanical balance and operation feel, greatly improving the dynamic balance during rotation, and the overall structure is compact, rigid, easy to manufacture and assemble BRIEF DESCRIPTION OF DRAWINGS In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the specific embodiments or prior art description will be briefly introduced.

[0022] Figure 1 Fig. 2 is a structural schematic diagram of the switch in the present application in the double-break position; Figure 2 Fig. 3 is a structural schematic diagram of the switch in the present application in the first position; Figure 3 Fig. 4 is a structural schematic diagram of the switch in the present application in the second position; Figure 4 Fig. 5 is a structural schematic diagram of the switch in the present application in the reverse direction; Figure 3 Figure 5 Fig. 6 is a structural schematic diagram of the connection structure of the driving member and the handle in the present application; Figure 6 Fig. 7 is a structural schematic diagram of the driving member in the present application; Figure 7 Fig. 8 is a structural schematic diagram of the moving contact assembly in the present application; Figure 8 Fig. 9 is a structural schematic diagram of the first moving contact frame in the present application; Figure 9 Fig. 10 is a structural schematic diagram of the second moving contact frame in the present application.

[0023] ​Explanation of reference signs: 1, driving member; 101, high cam section; 102, low cam section; 11, first cam; 111, first circular-arc protrusion; 112, first speed slide part; 12, second cam; 121, second circular-arc protrusion; 122, second speed slide part; 13, first clamping hole; 14, second clamping hole; 15, third clamping hole; 16, fourth clamping hole; 17, coaxial part; 18, rotating shaft; 2, moving contact assembly; 21, first moving contact frame; 22, first moving contact bridge; 23, second moving contact frame; 24, second moving contact bridge; 3, stationary contact assembly; 31, first stationary contact; 32, second stationary contact; 33, third stationary contact; 34, fourth stationary contact; 4, contact shaft; 5, elastic member; 6, limiting block; 7, limiting groove; 8, handle structure; 9, shell. DETAILED DESCRIPTION

[0024] The technical solutions of the present application will be described clearly and completely below in conjunction with the drawings. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the protection scope of the present application.

[0025] In the description of the present application, it should be noted that the terms "first", "second", "third" are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0026] In the description of the present application, it should be noted that, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connection" should be understood in a broad sense, for example, can be fixed connection, can also be detachable connection, or integrally connected; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present application can be understood according to the specific circumstances.

[0027] In addition, the technical features involved in the different embodiments of the present application described below can be combined with each other as long as there is no conflict.

[0028] Embodiment The present embodiment will be described in detail below in conjunction with the drawings: The present embodiment provides a contactor as described above Figures 1-9The switch shown in the switch includes a housing 9 and a contact mechanism and a driving member 1 arranged in the housing 9, the contact mechanism includes two groups of moving contact assemblies 2 arranged in the same direction in the housing 9, and two groups of static contact assemblies 3 respectively matched with the two groups of moving contact assemblies 2 for contact or disconnection, the two groups of moving contact assemblies 2 and the two groups of static contact assemblies 3 are respectively provided with two groups of moving contacts and two groups of static contacts for matched contact; the driving member 1 has a first position for driving the first group of moving contact assemblies 2 and static contact assemblies 3 to connect the first circuit, a second position for driving the second group of moving contact assemblies 2 and static contact assemblies 3 to connect the second circuit, and an initial position for driving the two groups of moving contact assemblies 2 and the two groups of static contact assemblies 3 to disconnect the corresponding circuit; The driving member 1 includes two driving cams arranged coaxially and staggered, the two groups of moving contact assemblies 2 are respectively inclined to the two groups of static contact assemblies 3 by the elastic member 5, and are connected to form a linkage matching with the two driving cams, the two driving cams drive the two groups of moving contact assemblies 2 and the two groups of static contact assemblies 3 to alternately connect when the driving member 1 switches between the first position and the second position, that is, when one group of moving contact assemblies 2 and static contact assemblies 3 are connected to close the switch, the other group of moving contact assemblies 2 and static contact assemblies 3 are disconnected to open the switch, so as to realize the state of one closing and one opening; and the two driving cams drive the two groups of moving contact assemblies 2 to overcome the pressure of the elastic member 5 to disconnect the two groups of static contact assemblies 3 when the driving member 1 is in the initial position, so as to realize the double opening state.

[0029] In the above embodiment, according to the double cam structure of the driving member 1 with coaxial staggered design, the two groups of moving contact assemblies 2 are connected to form a linkage matching with the double cam structure through the elastic member 5, and the energy storage and release of the elastic member 5 to the two groups of moving contact assemblies 2 realizes the alternating connection mechanism of the two groups of moving contact assemblies 2, the two driving cams control the moving track of the two groups of moving contact assemblies 2 by using the cam profile of each cam, and the elastic member 5 provides driving force for the rapid action of the two groups of moving contact assemblies 2, so that the connection and disconnection process is no longer dependent on the speed of manual operation, ensuring the consistency and reliability of each operation. The switch adopting the technical solution realizes the mechanical interlocking type alternating connection of the two groups of moving contact assemblies 2 through the linkage matching design between the double cam structure, the two groups of moving contact assemblies 2 and the elastic member 5, so that only one group of moving contact assemblies 2 is connected and the other group is kept disconnected when the driving member 1 switches between the first position and the second position, realizing the mechanical interlocking type alternating connection of the two groups of moving contact assemblies 2. This design prevents the risk of short circuit caused by simultaneous connection of the main and standby power supply, meets the safety standards of the switch, and only when the driving member 1 switches to the initial position, the two groups of moving contact assemblies 2 are driven by the high cam segment of the double cam to overcome the pressure of the elastic member 5, forcing the two groups of moving contact assemblies and the two groups of static contact assemblies to be completely separated, thereby maintaining the double opening state. This design simplifies the three-position switching structure, reduces the cost and operation complexity, realizes fast and reliable connection and disconnection, and improves the electrical performance, safety and service life of the switch.

[0030] The following will be combined Figures 1-6The specific structure of the driving member is described in detail as follows: Both driving cams are provided with high cam sections 101 and low cam sections 102 which are smoothly connected in outer periphery contour, so as to form a cam outer periphery contour with drop-off connection. The low cam sections 102 of the two driving cams are staggered on one side of the high cam sections 101 of the two driving cams. The two driving cams drive the two groups of moving contact assemblies 2 to move alternately through the cooperation of the high cam sections 101 and the low cam sections 102. The distance from the high cam section to the rotating shaft 18 is larger, i.e. the protrusion height is relatively larger, which actively pushes the moving contact assembly 2 to move away from the stationary contact assembly 3 to overcome the pressure of the elastic member 5 and forcibly break the circuit. Correspondingly, the two groups of moving contact assemblies 2 are provided with two contact shafts 4 which are in sliding contact with the outer periphery contour of the two driving cams respectively. The axis of the contact shaft 4 is parallel to the axis of the rotating shaft 18 of the driving member 1. The contact area is small and the friction is low, which reduces the energy loss in the transmission process, and the driving member 1 is more labor-saving. It needs to be understood that when any of the contact shafts 4 rolls along the high cam section 101 to the low cam section 102 of the driving cam, the corresponding moving contact assembly 2 is quickly moved to approach the stationary contact assembly 3 under the action of the spring member. When any of the contact shafts 4 rolls from the low cam section 102 to the high cam section 101 of the driving cam, the moving contact assembly 2 is moved away from the stationary contact assembly 3 to overcome the force of the spring member. The advantage of this structure design is that the driving member 1 drives the two contact shafts 4 to cooperate with the high cam sections 101 of the two driving cams respectively at the initial position. The two driving cams push the corresponding contact shafts 4 to the two groups of moving contact assemblies 2 through the respective high cam sections 101 to apply uniform and sufficient pushing force, stably overcome the pressure of the elastic member 5 to achieve forced breaking, avoid the situation that the contacts are welded and cannot be disconnected, so as to realize the simultaneous breaking of the corresponding circuits of the two groups of moving contact assemblies 2 and the two groups of stationary contact assemblies 3. When the driving member 1 is switched from the initial position to the first position or the second position, one of the contact shafts 4 is driven to cooperate with the high cam section 101 of one of the driving cams, and the other contact shaft 4 is driven to cooperate with the low cam section 102 of the other driving cam, i.e. only the low cam section 102 of one of the driving cams releases the elastic member 5 at all times, so that the corresponding one of the groups of moving contact assemblies 2 realizes closing, and the high cam section 101 of the other driving cam continuously presses the contact shaft 4 of the other group of moving contact assemblies 2, so that the other group of moving contact assemblies 2 remains in the open state. This double-cam alternating driving mode utilizes the drop-off structure of the low cam section to match the release rhythm of the elastic member 5, so that when the contact shaft slides along the low cam section, the elastic member 5 is used to quickly push the moving contact assembly to close, which ensures the closing speed and structurally eliminates the possibility of simultaneous closing of the two circuits, so as to form a physical structure constraint that "one group closes and the other group must break", realize mechanical hard interlocking, and eliminate the risk of short circuit.

[0031] Further preferably, the driving member 1 is provided with a rotating shaft 18 which is rotatably arranged in the driving member 1 and is provided with a driving cam 10 which is arranged on the outer periphery of the rotating shaft 18 and is provided with a high cam section 101 and a low cam section 102 which are smoothly connected in outer periphery contour, so as to form a cam outer periphery contour with drop-off connection. The low cam section 102 of the driving cam 10 is staggered on one side of the high cam section 101. The driving cam 10 drives the two groups of moving contact assemblies 2 to move alternately through the cooperation of the high cam section 101 and the low cam section 102. The distance from the high cam section to the rotating shaft 18 is larger, i.e. the protrusion height is relatively larger, which actively pushes the moving contact assembly 2 to move away from the stationary contact assembly 3 to overcome the pressure of the elastic member 5 and forcibly break the circuit. Correspondingly, the two groups of moving contact assemblies 2 are provided with two contact shafts 4 which are in sliding contact with the outer periphery contour of the driving cam 10 respectively. The axis of the contact shaft 4 is parallel to the axis of the rotating shaft 18 of the driving member 1. The contact area is small and the friction is low, which reduces the energy loss in the transmission process, and the driving member 1 is more labor-saving. It needs to be understood that when any of the contact shafts 4 rolls along the high cam section 101 to the low cam section 102 of the driving cam, the corresponding moving contact assembly 2 is quickly moved to approach the stationary contact assembly 3 under the action of the spring member. When any of the contact shafts 4 rolls from the low cam section 102 to the high cam section 101 of the driving cam, the moving contact assembly 2 is moved away from the stationary contact assembly 3 to overcome the force of the spring member. The advantage of this structure design is that the driving member 1 drives the two contact shafts 4 to cooperate with the high cam sections 101 of the two driving cams respectively at the initial position. The two driving cams push the corresponding contact shafts 4 to the two groups of moving contact assemblies 2 through the respective high cam sections 101 to apply uniform and sufficient pushing force, stably overcome the pressure of the elastic member 5 to achieve forced breaking, avoid the situation that the contacts are welded and cannot be disconnected, so as to realize the simultaneous breaking of the corresponding circuits of the two groups of moving contact assemblies 2 and the two groups of stationary contact assemblies 3. When the driving member 1 is switched from the initial position to the first position or the second position, one of the contact shafts 4 is driven to cooperate with the high cam section 101 of one of the driving cams, and the other contact shaft 4 is driven to cooperate with the low cam section 102 of the other driving cam, i.e. only the low cam section 102 of one of the driving cams releases the elastic member 5 at all times, so that the corresponding one of the groups of moving contact assemblies 2 realizes closing, and the high cam section 101 of the other driving cam continuously presses the contact shaft 4 of the other group of moving contact assemblies 2, so that the other group of moving contact assemblies 2 remains in the open state. This double-cam alternating driving mode utilizes the drop-off structure of the low cam section to match the release rhythm of the elastic member 5, so that when the contact shaft slides along the low cam section, the elastic member 5 is used to quickly push the moving contact assembly to close, which ensures the closing speed and structurally eliminates the possibility of simultaneous closing of the two circuits, so as to form a physical structure constraint that "one group closes and the other group must break", realize mechanical hard interlocking, and eliminate the risk of short circuit. Figures 5-6As shown, the driving member 1 is a double cam structure provided in the housing 9 by two driving cams linked through the same rotating shaft 18, the cam outer periphery profiles of the two driving cams are arranged in a symmetrical structure, and they are arranged at a preset angle along the circumferential direction of the rotating shaft, specifically, the two driving cams are divided into the coaxial and integrally linked first cam 11 and the second cam 12, and the two groups of moving contact assemblies 2 are divided into the first moving contact assembly matched with the first cam 11 and the second moving contact assembly 2 matched with the second cam 12, the high cam section 101 includes the first circular arc protrusion 111 provided on the outer periphery of the first cam 11 and the second circular arc protrusion 121 provided on the outer periphery of the second cam 12; the low cam section 102 includes the first speed sliding part 112 smoothly connected with the first circular arc protrusion 111 and the second speed sliding part 122 smoothly connected with the second circular arc protrusion 121, the first circular arc protrusion 111 and the second circular arc protrusion 121 partially overlap along the circumferential direction, the first speed sliding part 112 and the second speed sliding part 122 are arc-shaped speed sliding surfaces arranged at an angle along the circumferential direction, the distance from the outer profile surface of the first circular arc protrusion 111 to the rotating shaft 18 is the same as the distance from the outer profile surface of the second circular arc protrusion 121 to the rotating shaft 18, the distance from the first speed sliding part 112 to the rotating shaft is smaller than the distance from the first circular arc protrusion 111 to the rotating shaft, and the distance from the second speed sliding part 122 to the rotating shaft is smaller than the distance from the second circular arc protrusion 121 to the rotating shaft. Through the phase stagger angle design of coaxial linkage, it ensures that the first cam 11 and the second cam 12 have an absolute synchronization relationship in rotation angle and timing, and directly determines the phase difference of the first speed sliding part 112 and the second speed sliding part 122 in the circumferential direction, the two driving cams construct physical interlocking for the two groups of moving contact assemblies 2 through the staggered profile phase, and this structure arrangement, when the driving member 1 rotates from the initial position to any on position, due to the staggered angle distribution of the two driving cams, for example, the first cam 11 enters the low cam section 102 (first speed sliding part) to make the first moving contact assembly ready to be turned on, while the second cam 12 still maintains in the high cam section 101 (second circular protrusion) for a small angle, ensuring that the corresponding second moving contact assembly continues to remain disconnected, which mechanically forces the realization of the "ensure that one group of moving contact assemblies is completely disconnected, and then the other group of moving contact assemblies starts to close" first disconnecting and then closing logic, eliminates the risk of short circuit, and strengthens the forced disconnecting force of the switch, and improves the disconnecting reliability.

[0032] In order to realize stable and reliable mechanical locking when the driving member 1 switches among the three positions, as shown in the figure, Figure 6As shown, the first cam 11 includes first and second notches 13 and 14 arranged on the first circular protrusion 111, and the first and second notches 13 and 14 have the same distance to the rotating shaft 18 and are matched with the contact shafts 4 of one group of movable contact assemblies 2, so that the first group of movable contact assemblies 2 can be kept in the breaking state during the sliding stage of the contact shafts 4 and the first circular protrusion; the second cam includes third and fourth notches 15 and 16 arranged on the second circular protrusion 121, and the third and fourth notches 15 and 16 have the same distance to the rotating shaft 18 and are matched with the contact shafts 4 of the other group of movable contact assemblies 2, so that the second group of movable contact assemblies 2 can be kept in the breaking state during the sliding stage of the contact shafts 4 and the second circular protrusion 121; the first and third notches 13 and 15 are arranged in axial alignment, and the second and fourth notches 14 and 16 are arranged in circumferential stagger; due to the axial alignment of the first notch 13 of the first cam 11 and the second notch 14 of the second cam 12 and the arrangement of the notches on the respective high cam segments 101, when the driving member 1 is in the initial position, the two contact shafts 4 are respectively clamped in the first and third notches 13 and 15, and the two groups of movable contact assemblies 2 are locked in the highest lifting position by the double cams against the pressure of the elastic members 5, thereby providing strong holding force to ensure the breaking state and achieve forced double breaking and electrical isolation; due to the circumferential staggered arrangement of the second notch 14 of the first cam 11 and the fourth notch 16 of the second cam 12, when the driving member 1 is switched to the first position, the contact shaft 4 of the first movable contact assembly is contacted on the first speed sliding part 112 after being separated from the first notch 13, and at this time, the first movable contact assembly is contacted with a corresponding group of static contact assemblies 3 under the action of the spring, and at the same time, the contact shaft 4 of the second movable contact assembly is switched from the third notch 15 to the fourth notch position and is locked, and at this time, the second movable contact assembly is driven by the second circular protrusion to be disconnected with another corresponding group of static contact assemblies 3; when the driving member 1 is switched to the second position, the contact shaft 4 of the second movable contact assembly is contacted on the second speed sliding part 122 after being separated from the third notch 15, and at this time, the second movable contact assembly is contacted with a corresponding group of static contact assemblies under the action of the spring, and at the same time, the contact shaft 4 of the first movable contact assembly is switched from the first notch 13 to the third notch 15 and is locked, and at this time, the first movable contact assembly is driven by the first circular protrusion to be disconnected with another corresponding group of static contact assemblies 3, thereby achieving the switching effect that one group of static contact assemblies is connected and the other group is disconnected.

[0033] The two driving cams with the above structure form three clear mechanical locking points by designing four notches, which correspond to the initial position, the first position and the second position respectively, when the contact shaft 4 falls into the corresponding notch, the driving part 1 is mechanically clamped and cannot move by itself, the combination structure of the double cam and the multiple notches integrates the state locking, the safety interlocking and the force balance function, which ensures that the switch can be stably stayed at the preset station under any working condition, which prevents the change of the switch position caused by vibration, impact or non-human operation, and ensures the stability of the running state, the first notch 13 and the second notch 14 are axially aligned, which is the core of realizing the initial position locking, and the second notch 14 and the fourth notch 16 are arranged in a circumferential staggered manner, which is the core of realizing the mechanical interlocking of the first position and the second position, during the rotation of the driving part 1, when the contact shaft of a group of moving contact assemblies is clamped into the second notch 14 or the fourth notch 16 which is turned on, the contact shaft of the other group of moving contact assemblies must be on the speed sliding part of the cam, and the corresponding contact group is in a determined breaking state, which forcibly realizes the logic of breaking before making and absolutely prevents the short circuit of the double power supply.

[0034] In the embodiment, as shown in Figure 6 , the driving part 1 includes a coaxial part 17 integrally connecting the first cam 11 and the second cam 12, the coaxial part 17 is provided with an axle hole through which the rotating shaft 18 passes, the first cam 11 and the second cam 12 are distributed on the two sides of the coaxial part 17 in a circumferential staggered manner, and the handle structure 8 for driving the rotation of the driving part 1 is rotationally arranged on the shell 9. This driving part 1 integrally connects the first cam 11 and the second cam 12 through the coaxial part 17, so that they become a single and rigid functional part, which ensures that the relative phase angle is formed between the two cams, and in the rotation process of the driving part, the two cams move as a whole, and the time sequence relationship between the two cams driving the two groups of moving contact assemblies is not delayed or misplaced, which ensures the high reliability and consistency of the switch switching process, and the central symmetric structure design of the two cams optimizes the mechanical balance and the operation feeling, greatly improves the dynamic balance during rotation, and the overall structure is compact, rigid, easy to manufacture and assemble The specific structure of the moving contact assembly and the static contact assembly will be described in detail below Figures 1-4 , Figures 7-9 ​The first moving contact assembly comprises a first moving contact frame 21 movably arranged in the shell 9, and a first moving contact bridge 22 and a contact spring arranged on the first moving contact frame 21; the second moving contact assembly comprises a second moving contact frame 23 movably arranged in the shell 9, and a second moving contact bridge 24 and a contact spring arranged on the second moving contact frame 23; the elastic member 5 comprises two compression springs arranged at the bottom of the first moving contact frame 21 and the bottom of the second moving contact frame 23 respectively, one end of each of the two compression springs is positioned in the shell 9, and the other end is positioned in the bottom groove of the two moving contact frames; this structure design adopts two independent compression springs and two independent moving contact frames to cooperate, so that the first moving contact assembly and the second moving contact assembly are decoupled and do not interfere with each other in mechanical movement, which facilitates maintenance and adjustment, and realizes independent and parallel driving of the two moving contact assemblies 2. It is further preferred that two contact shafts 4 are arranged at the top of the first moving contact frame 21 and the second moving contact frame 23 respectively, the first moving contact frame 21 and the second moving contact frame 23 have a movement trend towards the first cam 11 and the second cam 12 under the action of the two compression springs, the contact shaft 4 of the first moving contact frame 21 is in contact with the outer contour of the first cam 11, and the contact shaft 4 of the second moving contact frame 23 is in contact with the outer contour of the second cam 12, wherein the first moving contact bridge 22 and the second moving contact bridge 24 are arranged staggered along the height direction of the two moving contact assemblies 2, and both have moving contact heads arranged towards the same side, and the two static contact assemblies 3 are arranged staggered in the shell, which comprises a first static contact 31 and a second static contact 32 arranged opposite to the first moving contact bridge 22, and a third static contact 33 and a fourth static contact 34 arranged opposite to the second moving contact bridge 24, the first static contact 31 and the third static contact 33 are connected in an integral structure and extend to the same incoming line end, and a connecting terminal is arranged on the incoming line side of the shell 9 to connect the first static contact 31 and the third static contact, the first static contact 31 and the second static contact 32 constitute a first static contact assembly matched with the first moving contact assembly, and the third static contact 33 and the fourth static contact 34 constitute a second static contact assembly matched with the second moving contact assembly, the outgoing line side of the shell 9 is provided with a connecting terminal connected with the second static contact 32 and the fourth static contact respectively, which simplifies the wiring and improves the stability of the incoming line, and when the first static contact 31 and the second static contact 32 are connected by the first moving contact bridge 22, a first circuit is turned on, and when the third static contact 33 and the fourth static contact 34 are connected by the second moving contact bridge 24, a second circuit is turned on.The two independent compression springs serve as elastic members 5 and provide a pushing force towards the cam for the first and second moving contact frames 23, which makes the contact shafts arranged on the top of the two moving contact frames always adhere to the outer contour of the two driving cams, and the moving contact assembly is unidirectionally driven to close by the force of the compression springs, the efficient energy storage and release mechanism is constructed by the cooperation of the two compression springs and the two moving contact frames, and the closing speed of the two moving contact assemblies is improved, which realizes the quick closing of the switching switch by the jumping of any group of contacts, greatly shortens the arc duration, and directly improves the switching capacity and electrical life of the switch; according to the breaking force of the switching switch, the driving cam actively provides the breaking force to directly overcome the force of the compression spring and any contact adhesion force, and realizes reliable and mechanical forced breaking, and the scheme considers the quick action and forced breaking by designing two independent moving contact assemblies 2 and cooperating with the double cam structure.

[0035] The housing 9 is provided with a guide groove structure for guiding the linear movement of the first moving contact frame 21 and the second moving contact frame 23, and the first and second moving contact frames are guided to move linearly by the guide groove, and the transverse deviation is limited; further preferably, as shown in Figures 8-9 The first moving contact frame 21 is provided with a group of limiting grooves 7 on the side surface facing the second moving contact frame 23, the limiting grooves 7 are arranged in the moving direction of the first moving contact frame 21, the second moving contact frame 23 is provided with a group of limiting blocks 6 corresponding to the limiting grooves 7 on the side surface facing the first moving contact frame 21, the limiting grooves 7 and the limiting blocks 6 are slidably connected, which restricts the relative position of the two groups of moving contact frames, ensures that the two groups of moving contact frames always maintain parallel and fixed distance, and there is no relative torsion and deviation, and the above structure can ensure that the two groups of moving contact frames move linearly and accurately in the preset direction, and the action does not interfere with each other, and the structural rigidity and vibration resistance are strengthened.

[0036] The working process of the switching switch of the embodiment will be described below. The driving member 1 is switched from the initial position to the first position: the driving member 1 is driven by external force to rotate synchronously, the contact shaft 4 of the first moving contact frame 21 is disengaged from the first notch 13 of the corresponding first cam 11, and the contact shaft 4 slides along the first circular-arc protrusion 111 of the first cam 11; at the same time, the third notch 15 of the second cam 12 is also disengaged from the contact shaft 4 of the corresponding second moving contact frame 23, and the contact shaft 4 slides along the second circular-arc protrusion 121; as the rotation angle increases, the first speed sliding part 112 of the first cam 11 is turned to the corresponding position of the contact shaft 4, the first moving contact frame 21 is quickly pushed upward by the pressure spring to release the accumulated force instantaneously, the first moving contact bridge 22 is quickly closed with the first group of static contact components, the first circuit is turned on, and because the two cams are designed to be circumferentially staggered, the contact shaft of the second moving contact frame 23 is still in the cooperation stage of the second circular-arc protrusion 121 and is locked in the fourth notch 16, so that the second moving contact frame 23 is continuously pressed downward, thereby driving the second moving contact bridge 24 to keep disconnected with the second group of static contact components, and the second circuit is turned off.

[0037] The driving member 1 is switched from the initial position to the second position: the driving member 1 is driven by external force to rotate synchronously, the contact shaft 4 of the first moving contact frame 21 is disengaged from the first notch 13 of the corresponding first cam 11, and the contact shaft 4 slides along the first circular-arc protrusion 111 of the first cam 11; at the same time, the third notch 15 of the second cam 12 is also disengaged from the contact shaft 4 of the corresponding second moving contact frame 23, and the contact shaft 4 slides along the second circular-arc protrusion 121; as the rotation angle increases, the second speed sliding part 122 of the second cam 12 is turned to the corresponding position of the contact shaft 4, the second moving contact frame 23 is quickly pushed upward by the pressure spring to release the accumulated force instantaneously, the second moving contact bridge 24 is quickly closed with the second group of static contact components, the second circuit is turned on, and at the same time, the contact shaft 4 of the first moving contact frame 21 is locked in the second notch 14 of the first circular-arc protrusion 111, so that the first moving contact frame 21 is continuously pressed downward, thereby driving the first moving contact bridge to keep disconnected with the first group of static contact components, and the first circuit is turned off.

[0038] Obviously, the above embodiments are only examples for clearly illustrating, but not limitation on the embodiments. Based on the above description, other different forms of changes or variations can be made by those skilled in the art. Here, all the embodiments cannot be exhausted, and the obvious changes or variations derived therefrom are still within the protection scope of the present application.

Claims

1. A changeover switch with high breaking and high making capabilities, comprising a housing (9) and a contact mechanism and a drive member (1) disposed in the housing (9), characterized in that: The contact mechanism includes two sets of moving contact components (2) disposed in the housing (9) in the same direction, and two sets of stationary contact components (3) respectively corresponding to and engaging with or disconnecting from the two sets of moving contact components (2); the driving member (1) has a first position for driving the first set of moving contact components (2) and stationary contact components (3) to connect to the first circuit, a second position for driving the second set of moving contact components (2) and stationary contact components (3) to connect to the second circuit, and an initial position for driving both sets of moving contact components (2) and both sets of stationary contact components (3) to disconnect from the corresponding circuit; The driving component (1) includes two driving cams that rotate coaxially and are offset to form a phase angle. The two sets of moving contact components (2) are directed towards the two sets of stationary contact components (3) by the elastic element (5) and are connected to the two driving cams to form a linkage. When the driving component (1) switches between the first position and the second position, the two driving cams drive the two sets of moving contact components (2) to alternately connect with the two sets of stationary contact components (3). When the two driving cams are in the initial position, they drive the two sets of moving contact components (2) to overcome the pressure of the elastic element (5) and disengage from the two sets of stationary contact components (3).

2. The changeover switch with high breaking capacity and high making capacity according to claim 1, characterized in that: Both drive cams have a high cam section (101) and a low cam section (102) with smooth outer peripheral contours to form a drop-connected cam outer peripheral contour. The low cam sections (102) of the two drive cams are staggered and set on one side of the high cam section (101). The two drive cams drive the two sets of moving contact components (2) to move alternately through the cooperation of the high cam section (101) and the low cam section (102).

3. The changeover switch with high breaking and high making capabilities according to claim 2, characterized in that: The two sets of moving contact components (2) are provided with two contact shafts (4) that slide in contact with the outer peripheral contours of the two drive cams respectively. When the drive member (1) is in the initial position, it drives the two contact shafts (4) to engage with the high cam sections of the two drive cams respectively. When the drive member (1) switches from the initial position to the first position or the second position, it drives one of its contact shafts (4) to engage with the high cam section of one of its drive cams, and drives the other contact shaft (4) to engage with the low cam section of the other drive cam.

4. The changeover switch with high breaking capacity and high making capacity according to claim 2 or 3, characterized in that: The driving component (1) is a double cam structure consisting of two driving cams linked together on the housing (9) via the same rotating shaft (18). The outer periphery of the two driving cams is arranged in a symmetrical structure, and the two are offset by a preset angle along the rotating shaft (18).

5. The changeover switch with high breaking and high making capabilities according to claim 4, characterized in that: The two drive cams are a first cam (11) and a second cam (12) that are coaxially integrated and linked. The high cam section (101) includes a first arc protrusion (111) on the outer periphery of the first cam (11) and a second arc protrusion (121) on the outer periphery of the second cam (12). The low cam section (102) includes a first fast sliding part (112) that is smoothly connected to the first arc protrusion (111) and a second fast sliding part (122) that is smoothly connected to the second arc protrusion (121). The first arc protrusion (111) and the second arc protrusion (121) partially overlap in the circumferential direction. The first fast sliding part (112) and the second fast sliding part (122) are arc-shaped fast sliding surfaces that are staggered left and right in the circumferential direction.

6. The changeover switch with high breaking capacity and high making capacity according to claim 5, characterized in that: The distance from the outer periphery of the first arc protrusion (111) to the rotation axis (18) is the same as the distance from the outer periphery of the second arc protrusion (121) to the rotation axis (18).

7. The changeover switch with high breaking capacity and high making capacity according to claim 5, characterized in that: The first cam (11) includes a first bayonet (13) and a second bayonet (14) spaced apart on the first arc protrusion (111). The first bayonet (13) and the second bayonet (14) are equidistant from the rotating shaft (18) and respectively engage with the contact shaft (4) of one of the moving contact components (2). The second cam (12) includes a third bayonet (15) and a fourth bayonet (16) spaced apart on the second arc protrusion (121). The third bayonet (15) and the fourth bayonet (16) are equidistant from the rotating shaft (18) and respectively engage with the other moving contact component (2). The contact shaft (4) is engaged; the first bayonet (13) and the third bayonet (15) are axially aligned, and the second bayonet (14) and the fourth bayonet (16) are circumferentially offset; when the two contact shafts (4) are engaged in the first bayonet (13) and the third bayonet (15) respectively, the driving member (1) is locked in the initial position; when one of the contact shafts (4) is engaged in the second bayonet (14) or the fourth bayonet (16), the driving member (1) is locked in the first position or the second position, so that the other contact shaft (4) is engaged and connected to the first fast sliding part (112) or the second fast sliding part (122).

8. The changeover switch with high breaking and high making capabilities according to any one of claims 5-7, characterized in that: The two sets of moving contact components (2) are divided into a first moving contact component that cooperates with the first cam (11) and a second moving contact component that cooperates with the second cam (12). The first moving contact component includes a first moving contact frame (21) movably disposed on the housing (9), a first moving contact bridge (22) connected to the first moving contact frame (21), and a contact spring. The second moving contact component includes a second moving contact frame (23) movably disposed on the housing (9), a second moving contact bridge (24) connected to the second moving contact frame (23), and a contact spring. The elastic element (5) includes components respectively disposed on the first moving contact frame (11) and the second moving contact bridge (24) connected to the second moving contact frame (23). Two compression springs at the bottom of the first movable contact (21) and the bottom of the second movable contact (23), and two contact shafts (4) are respectively set at the top of the first movable contact (21) and the second movable contact (23). Under the action of the two compression springs, the first movable contact (21) and the second movable contact (23) have a tendency to move toward the first cam (11) and the second cam (12), so that the contact shaft (4) of the first movable contact (21) contacts and engages with the outer periphery of the first cam (11), and the contact shaft (4) of the second movable contact (23) contacts and engages with the outer periphery of the second cam (12).

9. The changeover switch with high breaking capacity and high making capacity according to claim 8, characterized in that: The first moving contact bridge (22) and the second moving contact bridge (24) have moving contacts arranged facing the same side; the two sets of stationary contact assemblies (3) include a first stationary contact (31) and a second stationary contact (32) arranged opposite to the first moving contact bridge (22), and a third stationary contact (33) and a fourth stationary contact (34) arranged opposite to the second moving contact bridge (24). The first stationary contact (31) and the third stationary contact (33) are integrally connected and extend to the same inlet terminal.

10. The changeover switch with high breaking capacity and high making capacity according to claim 8, characterized in that: The housing (9) is provided with a guide groove structure to guide the first movable contact frame (21) and the second movable contact frame (23) to move linearly. The first movable contact frame (21) is provided with a set of limiting grooves (7) on the side facing the second movable contact frame (23). The limiting grooves (7) extend along the moving direction of the first movable contact frame (21). The second movable contact frame (23) is provided with a set of limiting blocks (6) slidably connected in the set of limiting grooves (7) on the side facing the first movable contact frame (21).

11. The changeover switch with high breaking capacity and high making capacity according to claim 5, characterized in that: The drive unit (1) includes a coaxial portion (17) integrally connected to the first cam (11) and the second cam (12). The coaxial portion (17) is provided with a shaft hole through which a rotating shaft (18) can pass. The first cam (11) and the second cam (12) are circumferentially offset on both sides of the coaxial portion (17). A handle structure (8) for driving the drive unit (1) to rotate is rotatably provided on the housing (9).

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