Teaching appliance

Abstract

The utility model discloses a teaching aid, and relates to the technical field of science and education equipment, the teaching aid comprises a basic shaft, a deformation assembly and a pulling member, the basic shaft extends along a first direction; the deformation assembly is provided with a mounting hole for the basic shaft to penetrate through, the deformation assembly rotates around the basic shaft, the two ends of the deformation assembly in the first direction have moving strokes which are relatively close to or away from each other, and the two ends of the deformation assembly in the first direction are relatively close to or away from each other to change the rotational inertia of the deformation assembly; the pulling piece and at least part of the deformation assembly are arranged in a limiting mode in the first direction, and the pulling piece is used for being pulled by a user so that the two ends of the deformation assembly in the first direction can be relatively close to or away from each other. According to the technical scheme provided by the utility model, the two ends of the deformation component in the first direction are relatively close to or far away from each other by pulling the pulling piece, so that the mass distribution of the deformation component is changed, the rotational inertia of the deformation component is further changed, and the technical effect of changing the angular velocity of the deformation component is achieved.

Description

Technical Field

[0001] This utility model relates to the field of scientific and educational equipment technology, and in particular to a teaching tool. Background Technology

[0002] Physics is inherently an experimental science, and experiments play a crucial role, especially in the teaching of basic science and engineering physics in junior high, high school, and university. Although there are many videos of various experiments available now, nothing stimulates students' interest as much as hands-on, on-site verification.

[0003] The Zhukovsky chair experiment is commonly used to visually verify the law of conservation of angular momentum. In this experiment, a person sits in a swivel chair, holding dumbbells with arms outstretched. Others push the chair, causing it to rotate. The person then retracts their arms, resulting in a significant increase in the chair's rotational speed. This experiment demonstrates the principle of conservation of angular momentum: angular momentum equals the moment of inertia multiplied by angular velocity. When the arms change from outstretched to retracted to chest level, the moment of inertia decreases, and the angular velocity increases.

[0004] However, it is difficult to find a swivel chair and dumbbells to conduct the experiment in the classroom, and the swivel chair used in daily life experiences a large amount of friction when rotating, resulting in a poor demonstration effect and low demonstrability. Utility Model Content

[0005] The main purpose of this invention is to provide a teaching tool that can be used in the classroom to verify the conservation of angular momentum.

[0006] To achieve the above objectives, the present invention proposes a teaching aid for demonstrating the conservation of angular momentum. The teaching aid includes: a base shaft, a deformable component, and a pulling member. The base shaft extends along a first direction. The deformable component has mounting holes for the base shaft to pass through. The deformable component rotates around the base shaft. The two ends of the deformable component in the first direction have relative moving distances, allowing the two ends to move closer or further apart to change the moment of inertia of the deformable component. The pulling member is positioned at least partially above the deformable component in the first direction. The pulling member is for use by a user to pull the deformable component so that the two ends in the first direction move closer or further apart.

[0007] In one embodiment, the deformable component further includes:

[0008] Two end cap assemblies are sleeved on the base shaft and spaced apart along a first direction;

[0009] A linkage assembly having a first link and a second link, one end of the first link being connected to a pivot of one of the end cap assemblies, the other end of the first link being connected to a pivot of one end of the second link, and the other end of the second link being connected to a pivot of another of the end cap assemblies.

[0010] In one embodiment, a plurality of link assemblies are provided, and the plurality of link assemblies are circumferentially spaced around the base axis.

[0011] In one embodiment, the teaching aid further includes a bearing disposed between the base shaft and the end cap assembly.

[0012] In one embodiment, the end cap assembly has a first extension and a second extension, the first extension and the second extension extending in a second direction and spaced apart in a first direction; the bearing is mounted between the first extension and the second extension.

[0013] In one embodiment, the end cap assembly includes:

[0014] The first cover has a third extension extending in a first direction, the third extension being formed through the mounting hole in the first direction, and one end of the third extension near the end of the base shaft extending in a second direction to form the first extension.

[0015] The second cover is disposed through a first direction and has a fourth extension extending along the first direction, the fourth extension extending along a second direction to form the second extension.

[0016] The third extension is threadedly connected to the fourth extension.

[0017] In one embodiment, the pulling member has a fifth extension extending along a first direction, the fifth extension being disposed through the first direction and sleeved on the base shaft, and the end of the fifth extension near the bearing extending along the first direction to form a sixth extension; the fifth extension is located between the base shaft and the first extension in a second direction, and the sixth extension is located between the bearing and the first extension in the first direction.

[0018] In one embodiment, the fifth extension is spaced apart from the first extension in a second direction; the sixth extension is spaced apart from the third extension in a second direction.

[0019] In one embodiment, the teaching aid further includes a plurality of balls, and the sixth extension has a plurality of grooves on the side facing the first extension, the plurality of grooves being for mounting the plurality of balls, the balls being used to abut against the first extension.

[0020] In one embodiment, the teaching aid further includes a sticker affixed to the end cap assembly or the linkage assembly; and / or,

[0021] At least one of the plurality of the linkage assemblies is painted.

[0022] The technical solution of this utility model uses a pulling member to make the two ends of the deformable component move closer or further apart in the first direction, thereby changing the mass distribution of the deformable component and thus changing the moment of inertia of the deformable component, thereby achieving the technical effect of changing the angular velocity of the deformable component. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0024] Figure 1 A schematic diagram of the structure of an embodiment of the teaching aid provided by this utility model.

[0025] Explanation of icon numbers:

[0026] 100. Teaching aids; 1. Base shaft; 2. Deformation assembly; 21. End cap assembly; 211. First cover; 2111. First extension; 21111. Groove; 2112. Third extension; 2113. Mounting hole; 212. Second cover; 2121. Second extension; 2122. Fourth extension; 22. Linkage assembly; 221. First link; 222. Second link; 3. Pulling element; 31. Fifth extension; 32. Sixth extension; 4. Bearing; 5. Ball bearing.

[0027] The realization of the purpose, functional features and advantages of this utility model will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0028] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present utility model.

[0029] It should be noted that if the embodiments of this utility model involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a specific posture. If the specific posture changes, the directional indicators will also change accordingly.

[0030] Furthermore, if the embodiments of this utility model involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the use of "and / or" or "and / or" throughout the text includes three parallel solutions. For example, "A and / or B" includes solution A, solution B, or a solution where both A and B are satisfied simultaneously. Furthermore, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. When the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this utility model.

[0031] However, it is difficult to find a swivel chair and dumbbells to conduct the experiment in the classroom, and the swivel chair used in daily life experiences a large amount of friction when rotating, resulting in a poor demonstration effect and low demonstrability.

[0032] This utility model proposes a teaching tool.

[0033] Please see Figure 1 In one embodiment of this utility model, the teaching aid 100 is used to demonstrate the conservation of angular momentum. The teaching aid 100 includes: a base shaft 1, a deformable component 2, and a pulling member 3. The base shaft 1 extends along a first direction. The deformable component 2 has a mounting hole 2113 for the base shaft 1 to pass through. The deformable component 2 rotates around the base shaft 1. The two ends of the deformable component 2 in the first direction have a relatively close or far apart travel. The two ends of the deformable component 2 in the first direction are relatively close or far apart to change the moment of inertia of the deformable component. The pulling member 3 is at least partially positioned above the deformable component 2 in the first direction. The pulling member 3 is used for the user to pull so that the two ends of the deformable component 2 in the first direction are relatively close or far apart.

[0034] In the technical solution of this utility model, the teaching aid 100 includes a base shaft 1, which extends along a first direction, generally a horizontal direction, to prevent the deformable component 2 from sliding along the base shaft 1 while rotating around it, thus avoiding the work done by sliding friction and affecting the verification of the conservation of angular momentum. The two ends of the deformable component 2 are brought closer or further apart to lengthen or compress it, thereby changing its moment of inertia. Since the deformable component 2 is rotating, its ends cannot be directly pulled. Therefore, a pulling member 3 is provided. The pulling member 3 is positioned at least at the upper limit of a portion of the deformable component 2 in the first direction. The pulling member 3 is not rotating and is used for the user to pull, so that the two ends of the deformable component 2 are brought closer or further apart in the first direction. Pulling the pull element 3 reduces the rotation radius of the deformable component 2, thereby reducing its moment of inertia. According to the conservation of angular momentum, the rotational speed of the deformable component 2 will increase. Pulling the pull element 3 increases the rotation radius of the deformable component 2, thereby increasing its moment of inertia. According to the conservation of angular momentum, the rotational speed of the deformable component 2 will decrease. The rotation of the deformable component 2 can be achieved by manually adjusting the pull element 3 to provide an initial rotational speed. The change in the angular velocity of the deformable component 2 can be clearly observed visually when the pull element 3 is pulled.

[0035] To allow the two ends of the deformable component 2 to move relatively closer or further apart in the first direction, and to cause a corresponding change in the moment of inertia during movement, the deformable component 2 further includes: two end cap assemblies 21 and a connecting rod assembly 22. The two end cap assemblies 21 are sleeved on the base shaft 1 and spaced apart along the first direction. The end cap assemblies 21 move along the first direction without deformation. As can be seen from the formula for calculating the moment of inertia, the moment of inertia corresponding to the end cap assembly 21 remains unchanged. Therefore, the change in moment of inertia needs to be reflected by the connecting rod assembly 22. Specifically, the connecting rod assembly 22 has a first connecting rod 221 and a second connecting rod 222. One end of the first connecting rod 221 is connected to the pivot of one of the end cap assemblies 21, and the other end of the first connecting rod 221 is connected to the pivot of one end of the second connecting rod 222. The other end of the second connecting rod 222 is connected to the pivot of the other end cap assembly 21. First, the way the link assembly 22 is arranged allows the two end cap assemblies 21 to be relatively close or far apart; in addition, the rotation radius of the first link 221 and the second link 222 will change during movement and rotation, so the moment of inertia can be adjusted.

[0036] As can be seen from the equation moment of inertia * angular velocity = angular momentum, moment of inertia and angular velocity are inversely proportional. When the moment of inertia of the connecting rod assembly 22 changes, the angular velocity will also change accordingly. To enhance the demonstration effect of the teaching aid 100, multiple connecting rod assemblies 22 are provided, and these multiple connecting rod assemblies 22 are circumferentially spaced around the base axis 1. When the two end cap assemblies 21 move closer or further apart, the moment of inertia of the multiple connecting rod assemblies 22 will change simultaneously, increasing the change in moment of inertia. Correspondingly, the angular velocity will also change significantly. A large change in angular velocity is beneficial for human observation and improves the demonstrativeness of the teaching aid 100. In addition, connecting the two end cap assemblies 21 with multiple connecting rod assemblies 22 can enhance the stability of the overall structure.

[0037] To prevent friction from affecting the verification of angular momentum conservation, it is impossible for there to be absolutely no friction between the end cap assembly 21 and the base shaft 1 during rotation. Therefore, the friction must be minimized. The teaching aid 100 also includes a bearing 4, which is positioned between the base shaft 1 and the end cap assembly 21. The bearing 4 reduces friction.

[0038] Because the end cap assembly 21 not only rotates but also slides, to prevent the bearing 4 from disengaging from the end cap assembly 21, the end cap assembly 21 has a first extension 2111 and a second extension 2121, which extend along a second direction and are spaced apart along a first direction; the bearing 4 is installed between the first extension 2111 and the second extension 2121. The first extension 2111 and the second extension 2121 limit the bearing 4, preventing it from disengaging from the end cap assembly 21.

[0039] Intuitively, by Figure 1 As can be seen from the end cap assembly 21 shown, if the end cap assembly 21 is integrally formed, then the bearing 4 cannot be installed between the first extension 2111 and the second extension 2121; therefore, the end cap assembly 21 needs to be set as a splicing of multiple parts. Specifically, the end cap assembly 21 includes: a first cover body 211 and a second cover body 212; the first cover body 211 has a third extension 2112 extending in a first direction, the third extension 2112 being disposed through the first direction to form the mounting hole 2113, and one end of the third extension 2112 near the end of the base shaft 1 extending in a second direction to form the first extension 2111; the second cover body 212 is disposed through the first direction and has a fourth extension 2122 extending in the first direction, the fourth extension 2122 extending in the second direction to form the second extension 2121; wherein, the bearing 4 is first placed between the first extension 2111 and the second extension 2121, and then the third extension 2112 and the fourth extension 2122 are threaded together.

[0040] To enable the pull member 3 to pull the end cap assembly 21 without rotating with it, the pull member 3 has a fifth extension 31 extending in a first direction. The fifth extension 31 is disposed through the base shaft 1 in the first direction. One end of the fifth extension 31 near the bearing 4 extends in the first direction to form a sixth extension 32. The fifth extension 31 is located between the base shaft 1 and the first extension 2111 in a second direction, and the sixth extension 32 is located between the bearing 4 and the first extension 2111 in the first direction. Both the bearing 4 and the sixth extension 32 are located between the first extension 2111 and the second extension 2121. The gap between the bearing 4 and the first extension 2111 is also greater than the width of the sixth extension 32. Therefore, the sixth extension 32 is not held by the bearing 4 and the first extension 2111 and does not rotate with the end cap assembly 21; it is only limited by the bearing 4 and the first extension 2111.

[0041] Friction can originate not only between the end cap assembly 21 and the base shaft 1, but also between the pull member 3 and the end cap assembly 21. Avoiding contact is the best way to prevent friction. In one embodiment, the fifth extension 31 is spaced apart from the first extension 2111 in the second direction; the sixth extension 32 is spaced apart from the third extension 2112 in the second direction. This requires a reasonable setting of the relationship between the radius of the bearing 4, the base shaft 1, the length of the first extension 2111, and the length of the sixth extension 32.

[0042] During the rotation of the end cap assembly 21, the pulling member 3 is pulled to make the sixth extension 32 abut against the first extension 2111, thereby moving the two end cap assemblies 21 away from each other. However, the friction generated when the sixth extension 32 abuts against the first extension 2111 results in a significant amount of work done by friction, which would seriously affect the verification of the conservation of angular momentum. Therefore, it is necessary to reduce the work done by friction. Thus, the teaching aid 100 also includes multiple ball bearings 5. The sixth extension 32 has multiple grooves 21111 on the side facing the first extension 2111, and these grooves 21111 are provided for the installation of the multiple ball bearings 5, which abut against the first extension 2111. Rolling friction is used instead of sliding friction, thereby reducing the work done by friction.

[0043] To make the observation of angular velocity more obvious and intuitive, the teaching aid 100 also includes stickers that are affixed to the end cap assembly 21 or the link assembly 22; and / or, at least one of the multiple link assemblies 22 is painted.

[0044] The above description is merely an exemplary embodiment of the present utility model and does not limit the patent scope of the present utility model. Any equivalent structural transformations made based on the technical concept of the present utility model and the contents of the present utility model specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present utility model.

Claims

1. A teaching aid for demonstrating the conservation of angular momentum, characterized in that, include: The base axis extends along the first direction; A deformable component has mounting holes for the base shaft to pass through, the deformable component rotates about the base shaft, and the two ends of the deformable component in a first direction have relatively close or far apart movable strokes, the two ends of the deformable component in the first direction being relatively close or far apart to change the moment of inertia of the deformable component. A pull member, at least at the upper limit of a portion of the deformable assembly in a first direction, is provided for a user to pull so that the two ends of the deformable assembly move closer or further apart in the first direction.

2. The teaching aid as described in claim 1, characterized in that, The deformable component further includes: Two end cap assemblies are sleeved on the base shaft and spaced apart along a first direction; A linkage assembly having a first link and a second link, one end of the first link being connected to a pivot of one of the end cap assemblies, the other end of the first link being connected to a pivot of one end of the second link, and the other end of the second link being connected to a pivot of another of the end cap assemblies.

3. The teaching aid as described in claim 2, characterized in that, The linkage assembly is provided in multiple ways, and the multiple linkage assemblies are arranged circumferentially around the base axis.

4. The teaching aid as described in claim 2, characterized in that, The teaching aid also includes a bearing, which is disposed between the base shaft and the end cap assembly.

5. The teaching aid as described in claim 4, characterized in that, The end cap assembly has a first extension and a second extension, the first extension and the second extension extending along a second direction and spaced apart along a first direction; the bearing is mounted between the first extension and the second extension.

6. The teaching aid as described in claim 5, characterized in that, The end cap assembly includes: The first cover has a third extension extending in a first direction, the third extension being formed through the mounting hole in the first direction, and one end of the third extension near the end of the base shaft extending in a second direction to form the first extension. The second cover is disposed through a first direction and has a fourth extension extending along the first direction, the fourth extension extending along a second direction to form the second extension. The third extension is threadedly connected to the fourth extension.

7. The teaching aid as described in claim 6, characterized in that, The pulling member has a fifth extension extending along a first direction, the fifth extension being disposed through the first direction and sleeved on the base shaft, and the end of the fifth extension near the bearing extending along the first direction to form a sixth extension; the fifth extension is located between the base shaft and the first extension in a second direction, and the sixth extension is located between the bearing and the first extension in the first direction.

8. The teaching aid as described in claim 7, characterized in that, The fifth extension is spaced apart from the first extension in a second direction; the sixth extension is spaced apart from the third extension in a second direction.

9. The teaching aid as described in claim 7, characterized in that, The teaching aid also includes multiple balls. The sixth extension has multiple grooves on the side facing the first extension. The multiple grooves are for mounting the multiple balls, and the balls are used to abut against the first extension.

10. The teaching aid as described in claim 2, characterized in that, The teaching aids also include stickers, which are affixed to the end cap assembly or the linkage assembly; and / or At least one of the plurality of the linkage assemblies is painted.

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