switch

Abstract

The application provides a switch. The switch comprises a switch housing, a swing lever assembly, a pin head assembly and a movable contact. The swing lever assembly comprises a swing lever body and an elastic piece. The swing lever body is swingably arranged in the switch housing and comprises a receiving cavity. The elastic piece is arranged in the receiving cavity. The pin head assembly comprises a pin and a spherical pin head. The pin is located between the elastic piece and the spherical pin head. The spherical pin head is swingably arranged in the receiving cavity relative to the pin. The movable contact is connected with the spherical pin head. Under the driving action of the swing lever body, the spherical pin head can drive the movable contact to swing. The switch can reduce the swing angle of the key, thereby reducing the thickness.

Description

TECHNICAL FIELD

[0001] Embodiments of the present application relate to the field of power equipment, and in particular to a switch. BACKGROUND

[0002] The existing switch, especially the swing lever switch (also known as the rocker switch), mostly sets a spring in the swing member, and the spring presses the movable contact piece to make it in contact with the static contact under force. The movable contact piece is swung back and forth to realize contact or separation with the static contact through the swing of the swing member, so as to realize the on-off of the switch. However, since the spring is twisted after being compressed in the swing process, the spring will exert a horizontal force on the movable contact piece, so that the movable contact piece is not in stable contact with the static contact, causing the virtual connection of the movable contact piece and the static contact and the virtual position of the key feeling. In order to avoid this problem, the swing angle of the key and the swing member of the switch needs to be increased, but this causes the thickness of the switch to increase a lot. SUMMARY

[0003] In order to solve the above problems, the embodiments of the present application provide a switch to at least partially solve the above problems.

[0004] According to a first aspect of the embodiments of the present application, a switch is provided, which comprises: a switch housing; a swing lever assembly, the swing lever assembly comprising a swing lever body and an elastic member, the swing lever body being swingably arranged in the switch housing, the swing lever body comprising a receiving cavity, and the elastic member being arranged in the receiving cavity; a ball press head assembly, the ball press head assembly comprising a ball and a spherical press head, the ball being located between the elastic member and the spherical press head, and the spherical press head being swingably arranged in the receiving cavity relative to the ball; and a movable contact piece, the movable contact piece being connected with the spherical press head, and the spherical press head being capable of driving the movable contact piece to swing under the driving action of the swing lever body.

[0005] Optionally, the spherical press head is provided with a contact piece groove, and the movable contact piece is at least partially inserted into the contact piece groove and tightly presses the spherical press head.

[0006] Optionally, the spherical press head comprises a press head body and two clamping plates extending outwardly along the press head body, the two clamping plates are kept at a certain interval, and the movable contact piece is at least partially inserted between the two clamping plates and tightly abuts against the two clamping plates.

[0007] Optionally, the press head body is provided with a body groove, the body groove is communicated with the gap formed by the two clamping plates to form the contact piece groove, and the movable contact piece is provided with a limiting protrusion, the body groove is matched with the limiting protrusion and limits the movement of the limiting protrusion in the direction perpendicular to the swing plane of the swing lever assembly.

[0008] Optionally, the elastic member comprises a spring, the marble comprises a marble body and a spring column, the spring column is fixedly arranged on the marble body, a stepped surface is formed between the marble body and the spring column, and the spring is sleeved on the spring column and abuts against the stepped surface at one end.

[0009] Optionally, the end surface of the marble matched with the spherical pressure head is a plane.

[0010] Optionally, the end surface of the marble matched with the spherical pressure head is an arc surface.

[0011] Optionally, the swing lever body is provided with a swing lever shaft, the swing lever shaft comprises a shaft seat and a protrusion, a top surface of the protrusion is a circular arc surface, and the top surface of the protrusion is in contact with the switch shell to enable the swing lever body to swing relative to the switch shell.

[0012] Optionally, the switch further comprises a conductive sheet and a static contact, the movable contact piece comprises a contact piece body and a swing arm, the contact piece body is connected with the spherical pressure head and is abutted against the conductive sheet by the spherical pressure head, a first end of the swing arm is connected to the contact piece body, and a second end of the swing arm is provided with a movable contact for matching with the static contact, and the movable contact is in contact with or separated from the static contact when the movable contact piece swings with the spherical pressure head.

[0013] Optionally, a first included angle is formed between an extension direction of the swing arm from the first end to the second end and an extension direction of the elastic member, and the first included angle is greater than or equal to 0° and less than 90°.

[0014] The switch shell of the switch (for example, the swing lever switch) provided in the embodiments of the present application is used for mounting and protecting the swing lever assembly, the marble pressure head assembly, the movable contact piece and the like. The swing lever body of the swing lever assembly is used for mounting the elastic member and the marble pressure head assembly and the like and driving the swing lever body to swing. The elastic member is used for applying an abutting force to the marble and the spherical pressure head to enable the movable contact piece to be abutted. Since the spherical pressure head can swing relative to the marble, when the elastic member is twisted to apply a force perpendicular to the extension direction to the marble, the force applied by the elastic member can be eliminated through the relative swing between the spherical pressure head and the marble, so that the force perpendicular to the extension direction is avoided from being applied to the movable contact piece through the spherical pressure head, the swing of the movable contact piece is avoided, the virtual position of the virtual contact and the pressing feeling of the switch are avoided, and the swing angle of the swing lever assembly can be reduced, so that the overall thickness of the switch is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0015] The following drawings are merely intended to schematically illustrate and explain the present application and do not limit the scope of the present application. In the drawings,

[0016] Figure 1 A perspective structural schematic view of a first view angle of a switch according to an embodiment of the present application is shown;

[0017] Figure 2Fig. 3 shows a longitudinal sectional perspective structural schematic diagram of a switch according to an embodiment of the present application;

[0018] Figure 3 Fig. 4 shows a partial enlarged view at I in Fig. 3; Figure 2

[0019] Figure 4 Fig. 5 shows a perspective structural schematic diagram of a switch according to an embodiment of the present application without a switch housing;

[0020] Figure 5 Fig. 6 shows a partial enlarged view at II in Fig. 5; Figure 4

[0021] Figure 6 Fig. 7 shows a perspective structural schematic diagram of a spherical indenter of a switch according to an embodiment of the present application;

[0022] Figure 7 Fig. 8 shows a longitudinal sectional perspective structural schematic diagram of a spherical indenter of a switch according to an embodiment of the present application; and

[0023] Figure 8 Fig. 9 shows a perspective structural schematic diagram of a movable contact of a switch according to an embodiment of the present application.

[0024] BRIEF DESCRIPTION OF THE DRAWINGS

[0025] 10, switch housing;

[0026] 20, swing lever body;

[0027] 211, shaft seat;

[0028] 212, protrusion;

[0029] 30, elastic member;

[0030] 41, pin;

[0031] 411, pin body;

[0032] 412, spring column;

[0033] 42, spherical indenter;

[0034] 421, indenter body;

[0035] 421a, body groove;

[0036] 422, clamping plate;

[0037] 50, movable contact;

[0038] 51, contact body;

[0039] 511, limiting protrusion;

[0040] ​​52, swing arm;

[0041] 521, moving contact;

[0042] 61, conductive sheet;

[0043] 62, stationary contact;

[0044] 71, first lead-out terminal;

[0045] 72, second lead-out terminal; and

[0046] 80, key. DETAILED DESCRIPTION

[0047] In order to have a clearer understanding of the technical features, objects and effects of the embodiments of the present application, the specific embodiments of the present application will be described with reference to the drawings.

[0048] Referring to Figures 1-8 , the present embodiment provides a switch, which comprises a switch housing 10, a swing lever assembly, a plunger head assembly and a moving contact sheet 50, the swing lever assembly comprises a swing lever main body 20 and an elastic member 30, the swing lever main body 20 is swingably arranged in the switch housing 10, the swing lever main body 20 comprises a receiving cavity, and the elastic member 30 is arranged in the receiving cavity; the plunger head assembly comprises a plunger 41 and a spherical head 42, the plunger 41 is located between the elastic member 30 and the spherical head 42, and the spherical head 42 is swingably arranged in the receiving cavity relative to the plunger 41; the moving contact sheet 50 is connected with the spherical head 42, and under the driving action of the swing lever main body 20, the spherical head can drive the moving contact sheet 50 to swing.

[0049] The switch, for example, can be a swing lever switch. The switch housing 10 of the switch is used for mounting and protecting the swing lever assembly, the plunger head assembly and the moving contact sheet 50 and the like. The swing lever main body 20 of the swing lever assembly is used for mounting the elastic member 30 and the plunger head assembly and the like, and drives them to swing. The elastic member 30 is used for applying a pressing force to the plunger 41 and the spherical head 42, so that the moving contact sheet 50 is pressed. Since the spherical head 42 can swing relative to the plunger 41, when the elastic member 30 is twisted to apply a force perpendicular to the extension direction to the plunger 41, the force applied by the twisted elastic member 30 can be eliminated through the relative swinging between the spherical head 42 and the plunger 41, so that the force perpendicular to the extension direction is avoided from being applied to the moving contact sheet 50 through the spherical head 42, the accidental swinging of the moving contact sheet 50 is avoided, the false position of the moving contact and the stationary contact of the switch when being pressed is prevented, and the swinging stroke of the swing lever assembly can be reduced, so that the overall thickness of the switch is reduced.

[0050] As shown in Figure 1 and Figure 2 , in the present embodiment, the thickness direction of the switch is Figure 1The Z direction shown in the figure, the length direction of the switch is Figure 1 The X direction is shown in the figure, and the width direction is Figure 1 Of course, this embodiment is only an example description and is not intended to be limiting.

[0051] In this embodiment, the switch housing 10 comprises an upper housing and a lower housing, which are detachably connected. The upper housing is primarily used to mount the rocker assembly and connect to a fixed object (such as a wall). The lower housing cooperates with the upper housing to protect the rocker assembly and the movable contact piece 50.

[0052] like Figures 2-4 As shown, the lower housing is further provided with a first lead terminal 71 and at least one second lead terminal 72, wherein the first lead terminal 71 and the second lead terminal 72 are both used to connect to the lead wire. The first lead terminal 71 and the second lead terminal 72 are both provided on the lower housing to be fixed by the lower housing.

[0053] In this embodiment, the first lead terminal 71 is connected to the movable contact piece 50. For example, the conductive piece 61 is fixedly connected to the first lead terminal 71, and at least a portion of the conductive piece 61 is fixedly mounted on the switch housing 10. Because the movable contact piece 50 is pressed against the conductive piece 61 by the force applied by the elastic member 30, it always maintains contact with the conductive piece 61, and thus the movable contact piece 50 is always connected to the first lead terminal 71.

[0054] The second lead-out terminal 72 is connected to a static contact 62, which is used to selectively contact the movable contact piece 50 to achieve on-off control of the switch. For example, in this embodiment, the number of the second lead-out terminals 72 can be two, and each second lead-out terminal 72 is provided with a static contact 62, and along the length direction of the switch (i.e. Figure 1 The two stationary contacts 62 are located on either side of the movable contact piece 50 in a one-to-one correspondence (in the X direction shown in FIG). In other words, the movable contact piece 50 is located between the two stationary contacts 62. Thus, when the movable contact piece 50 swings along the length of the switch, it contacts one of the two stationary contacts 62, thereby achieving on-off control of the switch. During this process, the position change of the movable contact piece 50 in the thickness direction of the switch (i.e., the travel in the thickness direction) is very small, which helps to reduce the thickness of the switch.

[0055] In this embodiment, in order to facilitate user operation and make the switch more integrated and beautiful, the switch may include a button 80, which is connected to the rocker assembly. In this way, when operating the switch, the user can press the button 80, so that the button 80 drives the rocker assembly to swing, thereby driving the moving contact piece 50 to swing, thereby realizing the on-off control of the switch.

[0056] like Figure 4As shown, the swing lever body 20 of the swing lever assembly includes a horizontal lever portion and a vertical lever portion, the horizontal lever portion and the vertical lever portion are connected, the horizontal lever portion is used to cooperate with the key 80 to realize the installation and fixation of the key 80, and the key 80 can push the swing lever body 20 to swing. For example, the horizontal lever portion can be connected with the key 80 through buckling. The vertical lever portion is provided with a receiving cavity to install the elastic element, the marble 41 and the spherical pressure head 42 and the like.

[0057] As shown in Figure 5 In order to ensure stable swing, the swing lever body 20 is provided with a swing lever shaft, the swing lever shaft includes a shaft seat 211 and a protrusion 212, the top surface of the protrusion 212 is a circular arc surface, and the top surface of the protrusion 212 is in contact with the switch housing 10 to make the swing lever body 20 swing relative to the switch housing 10.

[0058] As shown in Figure 4 and Figure 5 The two sides of the horizontal lever portion of the swing lever body 20 in the Y direction are both provided with the shaft seat 211, and each shaft seat 211 is provided with the protrusion 212. The shape, material and the like of the shaft seat 211 can be determined according to requirements, and the embodiment does not limit this.

[0059] The top surface of the protrusion 212 refers to the surface of the protrusion 212 away from the shaft seat 211. By setting the top surface of the protrusion 212 as a circular arc surface, the contact position of the protrusion 212 and the switch housing 10 forms a swing axis (the swing axis is perpendicular to the swing plane of the swing lever assembly), so that when any one end of the horizontal lever portion of the swing lever body 20 is pressed, the swing lever body 20 can swing around the swing axis. The swing lever shaft structure of this structure is simple, convenient to process, and can reduce the weight of the switch as a whole.

[0060] As shown in Figure 2 The vertical lever portion of the swing lever body 20 is used to install the elastic element 30, the marble 41 and the spherical pressure head 42. Among them, the elastic element 30 includes a spring, so that the production cost can be effectively reduced. Of course, in other embodiments, the elastic element 30 can also be of other structures, as long as it can provide the moving contact 50 with a pressing force to press it against the conductive sheet 61.

[0061] In this embodiment, the marble 41 is arranged between the elastic element 30 and the spherical pressure head 42, so that when the elastic element 30 is twisted, the twist of the elastic element 30 can be eliminated through the relative movement of the marble 41 and the spherical pressure head 42, and the contact instability of the moving contact 50 and the static contact 62 caused by the force generated by the twist of the elastic element 30 is avoided.

[0062] In addition, the arrangement of the ball 41 between the elastic member 30 and the spherical pressing head 42 can avoid the wear of the elastic member 30 to the spherical pressing head 42. When the elastic member 30 is a spring, the arrangement of the ball 41 can also avoid the problem that the spherical pressing head 42 is embedded into the inner ring of the spring, and the spring prevents the spherical pressing head 42 from swinging.

[0063] Optionally, as shown in Figure 3 In order to better cooperate with the spring, the ball 41 comprises a ball main body 411 and a spring column 412, the spring column 412 is fixedly arranged on the ball main body 411, and a stepped surface is formed between the ball main body 411 and the spring column 412. The spring is sleeved on the spring column 412, and one end of the spring abuts on the stepped surface. The ball main body 411 is mainly used for cooperating with the spherical pressing head 42. The stepped surface between the spring column 412 and the ball main body 411 can limit the spring, and also serves as a force applying surface of the spring, so that the spring can apply the abutting force to the movable contact 50 through the ball 41 and the spherical pressing head 42.

[0064] In order to ensure the spherical surface connection between the spherical pressing head 42 and the ball 41, so that the relative movement of the two is more stable and smooth, the end surface of the ball 41 cooperating with the spherical pressing head 42 is a plane. Alternatively, the end surface of the ball 41 cooperating with the spherical pressing head 42 is an arc surface. In this way, the spherical pressing head 42 and the ball 41 can be cooperated with each other, so that the spherical pressing head 42 can rotate smoothly.

[0065] In the embodiment, since the relative movement of the spherical pressing head 42 and the ball 41 can offset the force generated by the torsion of the elastic member 30, it is not necessary to arrange a large gap between the spherical pressing head 42 and the movable contact 50 to avoid the transmission of the force generated by the torsion of the elastic member 30 to the movable contact 50, so that the movable contact 50 can be tightly cooperated with the spherical pressing head 42. In this way, the spherical pressing head 42 only needs to swing a small angle to realize the contact or separation between the movable contact 50 and the stationary contact 62, so that the swing angle of the key 80 can be small, and the thickness of the switch can be reduced. Thus, the problem that the large gap between the movable contact and the pressing head causes the large virtual position between the movable contact and the pressing head, and the large swing angle of the key makes the thickness of the switch unable to be reduced is solved.

[0066] In one specific embodiment of the present application, the spherical pressing head 42 comprises a contact recess, and the movable contact 50 is at least partially inserted into the contact recess and tightly cooperated with the spherical pressing head 42. In this way, the reliable connection between the movable contact 50 and the spherical pressing head 42 is realized, and the dismounting and mounting of the movable contact 50 are very convenient.

[0067] Optionally, the spherical pressing head 42 comprises a pressing head body 421 and two clamping plates 422 extending outwardly from the pressing head body 421 and spaced apart from each other, the movable contact 50 is at least partially inserted between the two clamping plates 422 and abuts against the two clamping plates 422. The spherical pressing head 42 with such structure is more convenient to process, and the clamping plates 422 abutting against the movable contact 50 can ensure the contact area between the spherical pressing head and the movable contact 50, thereby ensuring that the movable contact 50 can be reliably driven to swing, and the diameter of the pressing head body 421 of the spherical pressing head 42 does not need to be set too large, which is helpful to ensure the thinness of the switch.

[0068] It should be noted that in the embodiment, the pressing head body 421 of the spherical pressing head 42 can be a complete sphere, or can be appropriately adjusted as needed, as long as the pressing head body 421 and the ball 41 are in spherical surface pair cooperation.

[0069] Optionally, as shown in Figure 6 the pressing head body 421 is provided with a body groove 421a, the body groove 421a is in communication with the gap formed by the two clamping plates 422 to form a contact piece groove, and the movable contact 50 is provided with a limiting protrusion 511, the body groove 421a is matched with the limiting protrusion 511 and limits the movement of the limiting protrusion 511 in the direction perpendicular to the swing plane of the swing lever assembly. By providing the body groove 421a on the pressing head body 421, the pressing head body 421 can limit the movable contact 50 to prevent its movement in the direction perpendicular to the swing plane (i.e. the direction parallel to the swing axis), and ensure that the movable contact 50 can accurately abut against the static contact 62 when swinging, avoiding misalignment between the movable contact 50 and the static contact 62.

[0070] As shown in Figure 7 in the embodiment, the movable contact 50 comprises a contact piece body 51 and a swing arm 52, the contact piece body 51 is connected with the spherical pressing head 42 and abuts against the conductive sheet 61 by the spherical pressing head 42, the first end of the swing arm 52 is connected to the contact piece body 51, and the second end of the swing arm 52 is provided with a movable contact 521 for cooperating with the static contact 62, and when the movable contact 50 swings with the spherical pressing head 42, the movable contact 521 contacts or separates from the static contact 62.

[0071] The extension direction of the swing arm 52 from the first end to the second end has a first included angle with the extension direction of the elastic member 30, the value of the first included angle is greater than or equal to 0° and less than 90°, which makes the setting position of the static contact 62 more flexible and better adaptable.

[0072] The switch is used in use, one end of the button 80 can be pressed, because the button 80 and the swing lever assembly are connected, when one end of the button 80 is pressed, the corresponding end of the swing lever body 20 of the swing lever assembly is pressed synchronously, so that the swing lever body 20 swings around the swing lever shaft, thereby driving the elastic piece 30, the billiard ball 41 and the spherical pressure head 42 to swing synchronously, the swing angle of the swing lever assembly is the same as the pressing angle of the button 80. Because the movable contact piece 50 is tightly pressed on the conductive sheet 61 by the elastic piece 30, and the movable contact piece 50 is tightly matched with the spherical pressure head 42, when the spherical pressure head 42 swings, the movable contact piece 50 swings, thereby making the movable contact 521 on the swing arm 52 of the movable contact piece 50 contact one of the two static contact pieces 62, thereby realizing the on-off control of the switch. In this process, because the movable contact piece 50 rotates synchronously with the spherical pressure head 42, the contact or separation of the movable contact piece 50 and the static contact piece 62 can be realized by swinging the button 80 at a smaller angle, and the stroke of the button 80 is smaller, thereby reducing the thickness of the switch.

[0073] If the elastic piece 30 is twisted in use, because the spherical pressure head 42 can rotate relative to the billiard ball 41, the reaction force caused by the twisting of the elastic piece 30 is eliminated, thereby making the spherical pressure head 42 tightly matched with the movable contact piece 50, and making the static contact piece 62 stably contact the movable contact piece 50.

[0074] The switch of the embodiment has the following beneficial effects:

[0075] Through the matching mode that the spherical pressure head and the billiard ball can move relative to each other, the reverse action force (i.e. the force that makes the movable contact piece and the static contact piece separate from each other) caused by the twisting of the elastic piece is eliminated, the contact between the movable contact piece and the static contact piece is stably ensured, and the false position of the button can be eliminated. In addition, the button can drive the swing lever assembly and the movable contact piece to move at a smaller swing angle, thereby breaking through the structural limitation of the existing switch, reducing the overall thickness of the switch, being suitable for being installed on different building walls and non-wall fixed objects, and improving the aesthetic appearance. Moreover, the switch has simple structure, convenient assembly and high reliability.

[0076] It should be understood that although the present specification is described according to various embodiments, not every embodiment contains only one independent technical solution, and the description manner of the specification is only for the sake of clarity, and those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be combined to form other embodiments that can be understood by those skilled in the art.

[0077] The above merely describes the specific implementation of the embodiments of the present application, and is not used to limit the scope of the embodiments of the present application. Any equivalent changes, modifications and combinations made by those skilled in the art without departing from the concept and principles of the embodiments of the present application shall fall within the scope of protection of the embodiments of the present application.

Claims

1. A switch, characterized by The switch comprises: a switch housing (10); a swing lever assembly comprising a swing lever body (20) and an elastic member (30), the swing lever body (20) being swingably arranged in the switch housing (10), the swing lever body (20) comprising a receiving cavity, the elastic member (30) being arranged in the receiving cavity; a ball press head assembly comprising a ball (41) and a spherical press head (42), the ball (41) being located between the elastic member (30) and the spherical press head (42), the spherical press head (42) being swingably arranged in the receiving cavity relative to the ball (41); and a movable contact (50) extending into the spherical press head (42) and abutting against the spherical press head (42), the spherical press head (42) being capable of driving the movable contact (50) to swing under the driving action of the swing lever body (20); the switch further comprises a conductive sheet (61), wherein the movable contact (50) comprises a contact body (51) connected with the spherical press head (42) and abutting against the conductive sheet (61) by the spherical press head (42).

2. The switch of claim 1, wherein The spherical press head (42) is provided with a contact recess, and the movable contact (50) extends at least partially into the contact recess and is in abutting engagement with the spherical press head (42).

3. The switch of claim 2, wherein The spherical press head (42) comprises a press head body (421) and two clamping plates (422) extending outwardly from the press head body (421), the two clamping plates (422) being spaced apart, and the movable contact (50) extends at least partially between the two clamping plates (422) and abuts against the two clamping plates (422).

4. The switch of claim 3, wherein The press head body (421) is provided with a body recess (421a) in communication with the gap formed between the two clamping plates (422) to form the contact recess, and the movable contact (50) is provided with a limiting protrusion (511), the body recess (421a) is in engagement with the limiting protrusion (511) and limits the movement of the limiting protrusion (511) in the direction perpendicular to the swing plane of the swing lever assembly.

5. The switch of claim 1, wherein The elastic member (30) comprises a spring, the ball (41) comprises a ball body (411) and a spring column (412), the spring column (412) is fixedly arranged on the ball body (411), and a stepped surface is formed between the ball body (411) and the spring column (412), the spring is sleeved on the spring column (412), and one end of the spring abuts against the stepped surface.

6. The switch according to any one of claims 1-5, characterized in that The end surface of the ball (41) in engagement with the spherical press head (42) is a plane.

7. The switch according to any one of claims 1-5, characterized in that The end surface of the ball (41) in engagement with the spherical press head (42) is an arc surface.

8. The switch of claim 1, wherein The swing lever body (20) is provided with a swing lever shaft, the swing lever shaft comprises a shaft seat (211) and a convex (212), the top surface of the convex (212) is a circular arc surface, and the top surface of the convex (212) is in contact with the switch shell (10) to enable the swing lever body (20) to swing relative to the switch shell (10).

9. The switch of claim 1, wherein The switch further comprises a static contact (62), the movable contact piece (50) further comprises a swing arm (52), the first end of the swing arm (52) is connected to the contact piece body (51), and the second end of the swing arm (52) is provided with a movable contact (521) for cooperating with the static contact (62); when the movable contact piece (50) swings with the spherical pressure head (42), the movable contact (521) is in contact or separated from the static contact (62).

10. The switch of claim 9, wherein The swing arm (52) has a first included angle between the extension direction from the first end to the second end and the stretching direction of the elastic member (30), and the value of the first included angle is greater than or equal to 0° and less than 90°.

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