CN113678333B - Assembly for indicating the operating state of a withdrawable circuit-breaker, corresponding withdrawable circuit-breaker and method for producing the same - Google Patents

Abstract

Embodiments of the present disclosure relate to an assembly (10) for indicating an operational state of a withdrawable circuit breaker, a corresponding withdrawable circuit breaker, and a method of producing the assembly (10). The assembly (10) includes a housing (20), an input member (30), an output member (40), and an indicator portion (46). The input member (30) is adapted to move relative to the housing (20) and includes a plurality of steps (34) at a periphery (32) of the input member, the plurality of steps (34) being stepped up against a direction of movement of the input member (30). The output member (40) is adapted to rotate about an axle (44) provided on the housing (20) and includes a resilient portion (42) at an end (41), the resilient portion (42) being adapted to engage each of the plurality of steps (34). An indication portion (46) is provided at the other end portion (43) of the output member (40) opposite to the elastic portion (42). In response to movement of the input member (30) relative to the housing (20), the resilient portion (42) disengages from a first step of the plurality of steps (34) and rotates about the shaft (44) to a degree to engage a second step adjacent the first step such that the output member (40) moves an end of the indicator portion (46) a distance in a direction perpendicular to the shaft (44). According to the embodiments of the present disclosure, the operating state of the circuit breaker can be clearly indicated with a simple structure.

Description

Assembly for indicating the operating state of a withdrawable circuit-breaker, corresponding withdrawable circuit-breaker and method for producing the same

Technical Field

Example embodiments of the present disclosure relate generally to indicating mechanisms in an electric field, and more particularly, to an assembly for indicating an operating state of a withdrawable circuit breaker, a corresponding withdrawable circuit breaker, and a method of producing the assembly.

Background

In an electric field, electrical devices can generally have a variety of operating states. For example, for a withdrawable circuit breaker, it may include different operating states such as connected, unblocked, tested, disconnected, etc. An indication of the operating state of the electrical device is very important. The operator can easily understand the current situation in the apparatus by clearly knowing the corresponding operation state. If an emergency occurs, the staff can take corresponding measures in time only by knowing the working state of the equipment.

Various solutions have been proposed to indicate the operating state of electrical equipment. For example, CN208479005U provides a withdrawable power distribution cabinet and a three-position display unit. However, such a solution can only provide at most three indication positions. If more positions are needed, the mechanism must be made very complex. This greatly limits the popularization of the power distribution cabinet.

Furthermore, in the conventional method, the movement pattern of the indicating mechanism is continuous movement, and the transition between the adjacent two operation states is slow. This produces an ambiguous indication that causes corresponding portions of both adjacent operating conditions to appear in the indication window. The staff member may be confused about the actual working state within the device. Therefore, it becomes necessary to generate an explicit indication of the adjacent operating states of the electrical devices.

Disclosure of Invention

Example embodiments of the present disclosure present a solution for clearly indicating the operational status of a withdrawable circuit breaker.

In a first aspect, example embodiments of the present disclosure provide an assembly for indicating an operational state of a withdrawable circuit breaker, including a housing, an input member, an output member, and an indication portion, the input member being adapted to move relative to the housing and including a plurality of steps at a periphery of the input member, the plurality of steps being stepped up against a direction of movement of the input member; the output member is adapted to rotate about an axis provided on the frame and includes a resilient portion at an end adapted to engage each of the plurality of steps; the indicating portion is disposed on the other end of the output member opposite the resilient portion, wherein in response to movement of the input member relative to the housing, the resilient portion disengages from a first one of the plurality of steps and rotates about the axis to a degree to engage a second one of the steps adjacent the first step such that the output member moves the end of the indicating portion a distance in a direction perpendicular to the axis.

According to the embodiment of the present disclosure, the indication part may conveniently and precisely indicate the operating state of the circuit breaker. In addition, the number of operating states to be indicated can be easily expanded.

In some embodiments, the indicator portion comprises a plurality of indicator frames at an end, and the housing is provided with a window adjacent the end of the indicator portion, wherein a first indicator frame of the plurality of indicator frames is adapted to align with the window; wherein a second indicator frame adjacent to the first indicator frame is aligned with the window in response to the indicator portion moving the distance. In this way, by providing corresponding indication boxes, a number of operating states can be indicated, and if the space is sufficient, the assembly allows to indicate more operating positions, which makes the circuit breaker suitable for more scenarios.

In some embodiments, wherein the indication portion may include: a pivot, an end of which is fixed to the frame; and a slot provided at the other end, the slot being adapted to move relative to a post provided on the output member, and wherein in response to rotation of the output member, the post moves the slot relative to the post and then rotates the indicator portion such that the end of the indicator portion moves the distance in a direction perpendicular to the axis. In this way, the indication portion can be actuated in a reliable manner to ensure accurate indication of the circuit breaker.

In some embodiments, the resilient portion includes a ramp and a cambered surface at an end thereof, the ramp being adjacent to the cambered surface, wherein a normal to the ramp passes through the friction circle about the axis. In this way, the elastic portion can be made stationary when the corresponding step is jumped. Therefore, the accuracy of the indication portion can be improved.

In some embodiments, the input member is disc-shaped and adapted to rotate about a center of rotation, and the periphery of the input member includes a plurality of surfaces, each step being formed by a respective adjacent surface of the plurality of surfaces, and the surfaces having progressively larger radii against the direction of movement. In this way, the assembly may be used with a rotating component. Thus, the range of use of the assembly is expanded.

In some embodiments, at least one of the plurality of surfaces is a circular surface centered on the center of rotation. In this way, by providing a simple and reliable configuration, an accurate indication action is ensured.

In some embodiments, the input member is a slider and is adapted to slide in a sliding direction perpendicular to the axis, and the periphery of the input member includes a plurality of surfaces, each step being formed by a respective adjacent surface of the plurality of surfaces, and the surfaces having progressively greater heights against the sliding direction. In this way, the range of use of the assembly can be expanded in a cost-effective manner.

In some embodiments, at least one of the plurality of surfaces is parallel to the sliding direction. In this way, an accurate indication action can be ensured.

In some embodiments, the assembly further comprises: a spring having one end fixed to the housing and the other end disposed between the shaft and the indicating portion, the spring allowing the elastic portion to engage with one of the steps. In this way, the reliability of the assembly is ensured.

In a second aspect, example embodiments of the present disclosure provide a withdrawable circuit breaker comprising the assembly of the first aspect.

In a third aspect, example embodiments of the present disclosure provide a method of producing an assembly for indicating an operational state of a withdrawable circuit breaker, comprising: providing a frame; providing an input member adapted to move relative to the housing and including a plurality of steps at a periphery of the input member, the plurality of steps ascending stepwise against a direction of movement of the input member; providing an output member adapted to rotate about an axis provided on the frame and including a resilient portion at an end adapted to engage each of the plurality of steps; and providing an indication portion on the other end of the output member opposite the resilient portion, wherein in response to movement of the input member relative to the housing, the resilient portion disengages from a first one of the plurality of steps and rotates about the axis to a degree to engage a second one of the steps adjacent the first step such that the output member moves the end of the indication portion a distance in a direction perpendicular to the axis.

Drawings

The above and other objects, features and advantages disclosed herein will become more readily apparent from the following detailed description taken in conjunction with the accompanying drawings. In the drawings, several example embodiments disclosed herein will be illustrated in the examples and in a non-limiting manner.

Fig. 1 illustrates a schematic diagram of components for indicating an operational state of a withdrawable circuit breaker in a first state, according to some example embodiments of the present disclosure;

FIG. 2 illustrates a schematic view of the assembly shown in FIG. 1 in a second state;

FIG. 3A illustrates a schematic diagram of the components shown in FIG. 1 while moving, according to some example embodiments of the present disclosure; and FIGS. 3B and 3C illustrate enlarged views of the assembly shown in FIG. 3A at different moments of movement;

FIG. 4 illustrates a perspective view of the assembly shown in FIG. 1, according to some example embodiments of the present disclosure;

FIG. 5 illustrates a schematic diagram of components according to additional example embodiments of the present disclosure; and

fig. 6 illustrates a perspective view of an indication portion according to some example embodiments of the present disclosure.

Detailed Description

The subject matter described herein will now be discussed with reference to several example embodiments. These embodiments are discussed only in order to enable those skilled in the art to better understand and thus practice the subject matter described herein, and are not intended to limit the scope of the subject matter in any way.

The terms "comprising" or "including" and variations thereof are to be interpreted as open-ended terms that mean "including, but not limited to. The term "or" should be read as "and/or" unless the context clearly indicates otherwise. The term "based on" should be read as "based at least in part on". The term "operable to" refers to a function, action, motion or state that can be achieved by an operation caused by a user or an external mechanism. The terms "one embodiment" and "an embodiment" should be read as "at least one embodiment. The term "another embodiment" should be read as "at least one other embodiment".

Unless specified or limited otherwise, the terms "mounted," "connected," "supported," and "coupled" and variations thereof are used broadly and encompass both direct and indirect mountings, connections, supports, and couplings. Furthermore, "connected" and "coupled" are not restricted to physical or mechanical connections or couplings. In the following description, the same reference numerals and labels are used to describe the same, similar or corresponding parts in the figures. Other definitions, both explicit and implicit, may be included below.

Some example embodiments of the present disclosure are described below with reference to fig. 1-6.

Fig. 1 illustrates a schematic diagram of an assembly 10 for indicating an operational state of a withdrawable circuit breaker, according to some example embodiments of the present disclosure. As shown, the assembly 10 includes, among other things, a housing 20, an input member 30, an output member 40, and a resilient portion 42. The input member 30 is adapted for movement relative to the housing 20. Further, the input member 30 includes a plurality of steps 34 at its periphery 32, wherein the plurality of steps 34 are stepped up against the direction of movement of the input member 30. The shaft 44 is provided on the frame 20. As shown in fig. 1, output member 40 is adapted to rotate about axis 44. The output member 40 has an end 41 and another end opposite to the end 41. As shown, the output member 40 includes a resilient portion 42 at the end 41 and an indicator portion 46 provided at the other end 43. The resilient portion 42 is adapted to engage each of the plurality of steps 34.

When the input member 30 moves relative to the housing 20, the elastic portion 42 is compressed and elastic energy is accumulated. With continued movement of the input member 30, the resilient portion 42 is pushed aside and disengages from the first one of the plurality of steps 34 to rotate about the shaft 44 to some extent. When the resilient portion 42 is sprung back by the elastic energy, it engages a second step which is adjacent to and higher than the first step. Since the resilient portion 42 "jumps" from the first step to the second step, the output member 40 moves the end of the indicator portion 46 a distance in a direction perpendicular to the axis 44.

According to an embodiment of the present disclosure, the indication portion 46 may spring up once when the elastic portion 42 jumps to a higher step. A clear indication is achieved so that the indication portion 46 does not provide confusing information showing both operating states.

The term "motion" as used herein refers to movement in a certain linear direction or rotation in a circular direction.

In some embodiments, as shown in fig. 1, the indicator portion 46 may include a plurality of indicator boxes 48 at the ends. The window 22 may be provided on the housing 20 adjacent the end of the indicator portion 46. Among the indicator boxes 48, a first indicator box of the plurality of indicator boxes 48 may be aligned with the window 22. When the indicator portion 46 is moved a distance, a second indicator frame adjacent to the first indicator frame is aligned with the window 22. In this way, when the input part 30 rotates, the user can see the movement of the indication frame from the outside. Thus, the user can know the current operating state in a convenient manner.

In some embodiments, the window 22 may be provided with a transparent cover. In this way, foreign objects such as dust can be prevented from entering the window 22. Thus, the indicator portion 46 may operate in a cleaner and safer environment.

In some embodiments, the cover may be made of transparent plastic to allow a user to view the indicator frame 48 through the window 22. The material of the cover may be any material known or to be developed in the future, such as transparent or translucent glass or other suitable material, so long as the material allows the user to view the indicator frame 48 through the window 22.

In some embodiments, the indicator portion 46 may include a pivot 462 at one end and a slot 464 at the other end. As shown in fig. 4, the pivot 462 is fixed to the frame 20. The slot 464 is adapted to move relative to a post 47 provided on the output member 40. As the output member 40 rotates, the post 47 moves the slot 464 relative to the post 47. The indicating portion 46 is thus rotated. In this way, the end of the indicating portion 46 moves a distance in a direction perpendicular to the shaft 44.

In some embodiments, the resilient portion 42 may include a chamfer 422 and a camber 424. As shown in fig. 5A, on the end of the elastic portion 42, the inclined surface 422 and the cambered surface 424 are provided adjacent to each other. The ramp 422 may be planar with its normal C passing through the axis 44 of the output member 40. As shown in fig. 3B, when the input member 30 moves in the movement direction R1, the corner 35 formed between the adjacent two steps pushes the inclined surface 422, and the elastic portion 42 starts to move relative to the corner 35. When the corner 35 of the input member 30 compresses the ramp 422, the line of action of the compressive force F (i.e., normal C) will also pass through the friction circle about the axis 44. It should be appreciated that the radius of the friction circle may be defined as the product of the coefficient of friction and the radius of the shaft 44. Therefore, when the step is compressed and is about to leave the elastic portion 42, no moment is generated to rotate the output member 40, and thus the output member 40 is self-locking. With the elasticity of the elastic portion 42 and the self-locking of the output member 40, an unclear indication of the circuit breaker can be avoided in a reliable manner.

According to the embodiments of the present disclosure, the operating state of the circuit breaker can be accurately indicated with a small number of parts. In addition, if more states are required, the assembly 10 of the present disclosure may also be adjusted without significantly complicating the assembly 10. For example, if six or more conditions are desired to be indicated, the assembly 10 may conveniently meet the above-described requirements by simply providing a corresponding number of steps on the surface of the input member 30.

In some embodiments, the input member 30 may be disk-shaped, which may rotate about a center of rotation 33. As shown in fig. 4, the periphery 32 of the input member 30 includes a plurality of surfaces 36. Each step is formed by a respective adjacent one of the plurality of surfaces 36.

When the disk rotates around the rotation center 33, the first step in contact with the elastic portion 42 compresses it and causes elastic potential energy to accumulate in the elastic portion 42. As the disc continues to rotate, the resilient portion 42 will be pushed away and the disc will be rotated forward by a certain angle. When the elastic portion 42 is sprung back by elastic potential energy, it will come into contact with a second step adjacent to the first step. Thus, the resilient portion 42 "jumps" to a step higher than the previous step and the indicating portion 46 correspondingly moves to the next position to indicate a different operating condition. With this arrangement, the operator driving the circuit breaker can transmit its internal motion to the disc, which in turn rotates the output member 40 along its axis 44, giving a clear indication of the circuit breaker position. This may lead to a better user experience.

In some embodiments, at least one of the plurality of surfaces 36 is a circular surface centered on the center of rotation 33. As shown in fig. 4, the input member 30 includes five arc segments 361-365. Each of the five arc segments is an arc on a respective circle, wherein the circles have radii that are different from each other. It will be appreciated that in this embodiment the phrase "step up" means that the circle has a larger radius against the direction of movement, as shown in figure 1. In this way, the resilient portion 42 is not actuated when the resilient portion 42 moves relative to the input member 30 over a single arc 365 of the same radius.

In this way, the output member 40 may remain stationary unless the resilient portion 42 moves from the first arc segment to the second arc segment. Therefore, the indicator frame 48 is skipped only when the elastic portion 42 is in contact with a different step. As shown in fig. 4, this only occurs when the spring 43 jumps from arc 365 to the next arc 364. Therefore, the accuracy of the indication can be improved.

Although an input member 30 in the form of a disk with five steps is shown in fig. 4, it should be understood that this is merely an example and does not set any limit to the scope of the present disclosure. Any other number of steps is also possible, such as three, four, six or more, which may depend on the needs of the user and the size of the assembly 10.

In some embodiments, as shown in FIG. 5, input member 30 may be a slider that slides in a sliding direction L1 perpendicular to axis 44. As shown, the periphery 32 of the input member 30 includes a plurality of surfaces 36. Each step is formed by a respective adjacent one of the plurality of surfaces 36.

When the slider moves in the sliding direction L1, the first step in contact with the elastic portion 42 compresses it and causes elastic potential energy to accumulate in the elastic portion 42. As the slider continues to slide, the resilient portion 42 will be pushed away and the slider will slide a distance forward. When the elastic portion 42 is sprung back by elastic potential energy, it will come into contact with a second step adjacent to the first step. Thus, the resilient portion 42 "jumps" to a step higher than the previous step and the indicating portion 46 correspondingly moves to the next position to indicate the next operating condition. With this arrangement, the operator driving the circuit breaker can transmit its internal motion to the slide, which in turn rotates the output member 40 along its axis 44, giving a clear indication of the circuit breaker.

In some embodiments, at least one of the plurality of surfaces 36 may be parallel to the sliding direction L1. As shown in fig. 5, the input member 30 in the form of a slider includes four segments 366 to 369. Each of the four segments is a planar face, wherein the faces have different levels from each other, resulting in steps having different heights from each other. It will be appreciated that in this embodiment the phrase "step up" means that the planar face has a greater height against the direction of movement, as shown in figure 5. In this way, the resilient portion 42 is not actuated when the resilient portion 42 moves relative to the input member 30 on the same horizontal single segment 369.

In this way, the output member 40 may remain stationary unless the resilient portion 42 moves from the first segment to the second segment. Therefore, the indicator frame 48 is skipped only when the elastic portion 42 is in contact with a different step. As shown in fig. 5, this only occurs when the resilient portion 42 jumps from segment 369 to the next segment 368. Therefore, the accuracy of the indication can be improved.

Although an input member 30 in the form of a slider is shown in fig. 5, it should be understood that this is merely an example and does not set any limit to the scope of the present disclosure. Any other number of steps is also possible, for example three, five or even more, which may depend on the needs of the user and the size of the assembly 10.

Fig. 6 illustrates an exemplary operating state of the withdrawable circuit breaker. As shown, the indication section 46 includes consecutive indication boxes 48 that read "Connect", "Unblock", "Test", "Unblock", and "Disconnect". It should be understood that the specific operating conditions described herein are merely examples and are not intended to limit the scope of the present disclosure in any way. The state can be adjusted according to the actual needs of the user.

In some embodiments, the resilient portion 42 may be made of a resilient material to allow the resilient portion 42 to be compressed by a corresponding step of the input member 30. In this way, the components are easier to assemble and the costs remain relatively low. It should be appreciated that the material may be any known or later developed material, such as PE (polyethylene), PP (polypropylene) or other suitable material, so long as the material provides the elastic portion 42 with a suitable degree of elasticity 42.

In some embodiments, the size of the components (e.g., the height of each indicator frame, the length of the output component 40, the arc length of each step 34, etc.) may be determined based on the actual environment, such that when the output component 40 jumps once, the indicator frame may jump once as well. In some embodiments, the distance that the end of the indicating portion 46 moves may be equal to the height of the window 22, such that the corresponding indicating frame may be clearly observed from the outside through the window 22. In this way, a situation in which only a portion of the corresponding indication frame can be seen can be avoided.

In some embodiments, the indicator portion 46 may be integrally formed with the output member 40 when space in the circuit breaker is sufficient. In this way, the price of the configuration can be made lower and more reliable. In addition, space can be fully utilized.

In some embodiments, the input member 30 may be directly connected to the operator's driving element. In additional embodiments, the input member 30 may be connected to the drive element through one or more intermediate components. In this way, movement inside the circuit breaker can be transmitted to the input member 30, which allows the indication portion to indicate the operating state of the circuit breaker.

In some embodiments, the assembly 10 may also include a spring 50 having an end secured to the housing 20. As shown in fig. 1, the other end of the spring 50 is disposed between the shaft 44 and the indicating portion 46. The spring 50 may act as a return spring and facilitate engagement of the resilient portion 42 with one of the plurality of steps 34.

In some embodiments, the spring 50 may take the form of a compression spring. It should be appreciated that other forms of springs are possible, such as torsion springs, leaf springs, or wire springs, so long as the spring 50 can exert an elastic force to assist the engagement and disengagement of the elastic portion 42 from the input member 30.

In some embodiments, the amplitude of the swing of the output member 40 may be reduced if only a few operating conditions need to be indicated. In this case, the spring 50 may be omitted, and instead, a portion of the output member 40 may be made flexible so that the elastic portion 42 engages with one of the steps.

Referring back to fig. 3A, when the input member 30 rotates against the movement direction R1, the elastic portion 42 moves from a higher step to a lower step. The indicator portion 46 may thus be reversed. In this way, the indicator portion 46 can be moved quickly in both directions. Therefore, the working state of the circuit breaker can be flexibly indicated.

In a second aspect, example embodiments of the present disclosure provide a withdrawable circuit breaker. The withdrawable circuit breaker comprises the assembly 10 of the first aspect.

It should be understood that the withdrawable circuit breaker described herein is for illustrative purposes only and is not limiting of the use of the assembly 10. The assembly 10 according to the present disclosure may be used with other electrical devices such as low voltage circuit breakers and high voltage circuit breakers.

In a third aspect, example embodiments of the present disclosure provide a method of producing an assembly 10 for indicating an operational state of a withdrawable circuit breaker. It is to be understood that the apparatus, structure or process involved in the method has been described above with reference to fig. 1 to 6, and that details will not be described below for the sake of brevity.

Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims (10)

1. An assembly (10) for indicating an operational status of a withdrawable circuit breaker, comprising:

a frame (20);

an input member (30) adapted to move relative to the housing (20) and comprising a plurality of steps (34) at a periphery (32) of the input member, the plurality of steps (34) being stepped up against a direction of movement of the input member (30);

an output member (40) adapted to rotate about an axis (44) provided on the frame (20) and comprising at an end (41) a resilient portion (42), the resilient portion (42) being adapted to engage with each of the plurality of steps (34); and

an indicating portion (46) provided at the other end portion (43) of the output member (40) opposite to the elastic portion (42),

wherein in response to movement of the input member (30) relative to the housing (20), the resilient portion (42) disengages from a first one of the plurality of steps (34) and rotates about the axis (44) to a degree to engage a second one of the steps adjacent the first step such that the output member (40) moves an end of the indicator portion (46) a distance in a direction perpendicular to the axis (44),

wherein the indication portion (46) includes:

a pivot (462) fixed at an end to the frame (20); and

a slot (464) provided at the other end, the slot (464) being adapted to move relative to a post (47) provided on the output member (40), and

wherein in response to the rotation of the output member (40), the post (47) moves the slot (464) relative to the post (47) and then rotates the indicator portion (46) such that the end of the indicator portion (46) moves the distance in a direction perpendicular to the axis (44).

2. The assembly (10) of claim 1, wherein

The indicator portion (46) comprises a plurality of indicator frames (48) at an end, and the housing (20) is provided with a window (22) adjacent to the end of the indicator portion (46), wherein a first indicator frame of the plurality of indicator frames (48) is adapted to be aligned with the window (22);

wherein a second indicator frame adjacent to the first indicator frame is aligned with the window (22) in response to the indicator portion (46) moving the distance.

3. The assembly (10) of claim 1, wherein

The resilient portion (42) comprises a bevel (422) and a cambered surface (424) at its end, the bevel (422) being adjacent to the cambered surface (424), wherein a normal (C) of the bevel (422) passes through a friction circle around the shaft (44).

4. The assembly (10) of claim 1, wherein

The input member (30) is disc-shaped and adapted to rotate about a center of rotation (33), and the periphery (32) of the input member (30) comprises a plurality of surfaces (36), each of the steps being formed by respective adjacent ones of the plurality of surfaces (36), and the surfaces having progressively larger radii against the direction of movement.

5. The assembly (10) of claim 4, wherein

At least one of the plurality of surfaces (36) is a circular surface centered on the center of rotation (33).

6. The assembly (10) of claim 1, wherein

The input member (30) is a slider and is adapted to slide along a sliding direction (L1) perpendicular to the shaft (44), and the periphery (32) of the input member (30) includes a plurality of surfaces (36), each of the steps being formed by respective adjacent surfaces of the plurality of surfaces (36), and the surfaces having progressively larger heights against the sliding direction (L1).

7. The assembly (10) of claim 6, wherein

At least one of the plurality of surfaces (36) is parallel to the sliding direction (L1).

8. The assembly (10) of claim 1, further comprising:

a spring (50) having one end fixed to the housing (20) and the other end disposed between the shaft (44) and the indicator portion (46), the spring (50) allowing the resilient portion (42) to engage with one of the plurality of steps (34).

9. Withdrawable circuit breaker comprising an assembly (10) according to any one of claims 1 to 8.

10. A method of producing an assembly (10) for indicating an operational status of a withdrawable circuit breaker, comprising:

providing a frame (20);

-providing an input member (30) adapted to move relative to the housing (20) and comprising a plurality of steps (34) at a periphery (32) of the input member, the plurality of steps (34) being stepped up against a direction of movement of the input member (30);

-providing an output member (40) adapted to rotate about an axis (44) provided on the frame (20) and comprising at an end (41) a resilient portion (42), the resilient portion (42) being adapted to engage with each of the plurality of steps (34); and

an indication portion (46) is provided at the other end (43) of the output member (40) opposite to the elastic portion (42),

wherein in response to movement of the input member (30) relative to the housing (20), the resilient portion (42) disengages from a first one of the plurality of steps (34) and rotates about the axis (44) to a degree to engage a second one of the steps adjacent the first step such that the output member (40) moves the indicator portion (46) a distance in a direction perpendicular to the axis (44),

wherein the indication portion (46) includes:

a pivot (462) fixed at an end to the frame (20); and

a slot (464) provided at the other end, the slot (464) being adapted to move relative to a post (47) provided on the output member (40), and

wherein in response to the rotation of the output member (40), the post (47) moves the slot (464) relative to the post (47) and then rotates the indicator portion (46) such that the end of the indicator portion (46) moves the distance in a direction perpendicular to the axis (44).