Apparatus for demonstrating the composition of two forces in a straight line

Abstract

The utility model discloses a demonstration instrument of the synthesis of two forces on a straight line, including demonstration panel, spring, force sensing module and laser marking module. The force sensing module contains at least three force sensors fixed on the panel through the angle code, and each sensor is connected with the wire locker through the conversion joint, and the force applying end is arranged in the coplanar arrangement with the spring center line, to ensure that the pulling force is strictly collinear. The laser marking module is composed of a movable laser pen and an optical fiber fixed at the lower end of the spring, and the deformation is accurately positioned by the optical fiber light emission. The utility model discloses a flat pasteable force sensor and coplanar layout structure, solves the non-collinear error problem caused by the thickness of the traditional force meter, and combines laser positioning. The optical fiber body light emission marking replaces manual marking, significantly reduces the parallax, improves the accuracy and visualization effect of deformation reproduction, and the device structure is scientific, the demonstration result is intuitive and accurate, effectively improves the teaching effect, and is beneficial to the cultivation of students' rigorous scientific research spirit.

Description

Technical Field

[0001] This utility model relates to the field of education, specifically a demonstration device for the synthesis of two forces on the same straight line. Background Technology

[0002] In junior high school physics mechanics teaching, the concept of "composition of two forces along the same straight line" is the cornerstone for students to establish the concepts of resultant force and component force, and to understand the idea of ​​equivalent substitution. However, for a long time, conventional experimental schemes used to demonstrate this core law have had limitations to varying degrees. These limitations directly affect the scientific validity of experimental conclusions and the rigor of the teaching process, constituting the core problem that this technical solution aims to address.

[0003] Currently, the most common approach in teaching practice stems from the design of mainstream textbooks, which involves using two spring balances to apply a pulling force to the same object. The initial intention of this approach is to visually demonstrate the magnitude of the force, but its inherent structural flaws lead to fundamental errors. Because the spring balances themselves are quite thick, when they apply a pulling force to the object one after the other, the two forces do not actually act along the ideal straight line, but rather there is an unavoidable angle between them. This creates a contradictory situation: the experiment attempts to verify the conclusion of an ideal model (collinear forces), but the apparatus used cannot meet the basic premise of that model. This systematic error originating from the instrument itself not only affects the accuracy of the data but also has a potential negative impact on students' development of a rigorous scientific attitude.

[0004] To address the aforementioned collinearity problem, another approach is to introduce a fixed pulley to change the direction of the force. While this method theoretically guarantees collinearity of the tension, it introduces new teaching challenges. Concepts such as fixed pulleys and rope friction are advanced knowledge for students who haven't yet systematically studied simple machines. Teachers often have to simply state the conclusions, rendering the process of guiding students to actively explore merely a formality. More importantly, the introduction of pulleys introduces additional variables such as friction and rope mass. These non-core factors distract students and interfere with their focus on and understanding of the core concept of "resultant force."

[0005] In addition, there are some innovative approaches that attempt to verify the results from the perspective of changes in motion state, such as finding the resultant force by analyzing the motion parameters of the cart under different forces. While the ideas are novel, these approaches often rely on fixed pulleys and also face questions about the rigor of their underlying principles. Especially when dealing with the composition of forces in opposite directions, simple force ratios often fail to ensure strict equivalence between the two motion dynamic states, making the experimental verification process difficult to justify and failing to achieve the intended teaching effect.

[0006] In conclusion, existing technologies, whether constrained by inherent errors in instrument structure or by introducing advanced knowledge and complex factors that formalize the inquiry process, fail to accurately, intuitively, and efficiently serve teaching objectives. Therefore, developing a new demonstration instrument that fundamentally guarantees collinearity of forces, focuses on core concepts, and is easy and intuitive to operate has become an urgent need to improve the teaching quality of this knowledge point. Utility Model Content

[0007] This utility model aims to solve at least one of the technical problems existing in the prior art. To this end, this utility model proposes a demonstration device for the synthesis of two forces on the same straight line, comprising:

[0008] A display panel, on which a power module is installed;

[0009] A spring, vertically fixed to the display panel, is used to visually demonstrate the effect of force through deformation;

[0010] The force sensing module includes at least three force sensors and a digital display board corresponding to each force sensor. Each force sensor is fixed to the display panel by a corner bracket. A wire lock is fixed to the force sensor by a conversion connector. The digital display board is disposed on the surface of the display panel and is provided with a switch and a zeroing button.

[0011] A laser marking module includes a laser pointer and an optical fiber. The optical fiber is fixed to the lower end of the spring, and the laser pointer is slidably disposed on the display panel. During the sliding process, the laser pointer is used to illuminate the optical fiber to mark the deformation position of the spring.

[0012] Each of the locking devices is connected to the lower end of the spring via a rope, and the force-applying end of each of the force sensors is coplanar with the center line of the spring, ensuring that the force applied to the spring is on the same straight line.

[0013] Furthermore, the number of force sensors is three, including a first force sensor, a second force sensor, and a third force sensor.

[0014] Furthermore, the first force sensor is located on the lower left side of the spring, the second force sensor is located on the lower right side of the spring, the third force sensor is located on the upper right side of the spring, and each of the locking devices is located at one end close to the spring.

[0015] Furthermore, the laser pointer is mounted on a metal track via a positioning slider, the metal track is fixed to the surface of the display panel, and the positioning slider is provided with bolts for adjusting the tightness.

[0016] Furthermore, the optical fiber is fixed to the lower hook of the spring via an optical fiber corner bracket, and the upper end of the spring is connected to the three-way connecting block via a perforated metal sheet and fixed to the display panel.

[0017] Furthermore, the locking device is a one-way locking device, used to lock the rope during the experiment.

[0018] Furthermore, the display panel is an acrylic sheet with multiple sets of mounting holes on its surface for fixing various module components.

[0019] Compared with the prior art, the present invention, by adopting the above technical solution, has the following advantages:

[0020] This invention solves the problem of non-collinearity error caused by thickness in traditional force gauges by using a flat-mountable force sensor and a coplanar layout structure. Combined with laser positioning, it replaces manual marking with fiber optic all-light-emitting marks, significantly reducing parallax and improving the accuracy and visualization of deformation reproduction. The device has a scientific structure, and the demonstration results are intuitive and accurate, effectively improving teaching results and helping to cultivate students' rigorous scientific inquiry spirit. Attached Figure Description

[0021] Figure 1 This is an overall drawing of the present utility model;

[0022] Figure 2 This is a front view of the digital display panel of this utility model;

[0023] Figure 3 This utility model Figure 1 Enlarged view of point A in the middle;

[0024] Figure 4 This utility model Figure 1 Enlarged view at point C;

[0025] Figure 5 This utility model Figure 1 Enlarged view of section B in the middle.

[0026] The components include: 1. Display panel; 2. Power module; 3. Spring; 4a. First force sensor; 4b. Second force sensor; 4c. Third force sensor; 5. Digital display board; 51. Switch button; 52. Zeroing button; 6. Metal track; 7. Metal sheet; 8. T-hole connecting block; 9. Positioning slider; 10. Laser pointer; 11. Bolt; 12. Adapter; 13. Wire lock; 14. Fiber optic corner bracket. Detailed Implementation

[0027] The principles and features of this utility model are described below with reference to the accompanying drawings. The examples given are only for explaining this utility model and are not intended to limit the scope of this utility model.

[0028] In the description of this utility model, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", "clockwise" and "counterclockwise" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0029] like Figures 1 to 5 As shown, this utility model provides a demonstration device for the synthesis of two forces on the same straight line, including a display panel 1, a spring 3, a force sensing module and a laser marking module.

[0030] A power module 2 is installed on one side of the display panel 1.

[0031] The deformation of spring 3 will visually reflect the magnitude of the resultant force it experiences. The upper end of spring 3 is connected to a thin metal sheet 7 with a hole in the middle, which in turn is connected to a three-way connecting block 8, and finally fixed to the display panel 1. At the hook at the lower end of spring 3, an optical fiber angler 14 is used to secure the end of the optical fiber tightly against the hook. The optical fiber angler 14 can gently constrain the optical fiber, avoiding excessive bending that would cause light loss, and ensuring that the laser can be efficiently guided.

[0032] The force sensing module includes three force sensing units with identical structures. Each unit consists of a force sensor, a wire locker 13, a conversion connector 12, and a digital display board 5. The wire locker 13 is rigidly connected to the sensor through the conversion connector 12.

[0033] To demonstrate the synthesis of two forces along a straight line, both in the same direction and in opposite directions, this invention preferably uses three force sensors. The specific layout is as follows: The first force sensor 4a is mounted on the display panel 1 via a corner bracket, located on the lower left side of the spring 3. The second force sensor 4b is also mounted via a corner bracket, located on the lower right side of the spring 3, and can be at the same height as the first force sensor 4a in the vertical direction or slightly offset. The third force sensor 4c is mounted on the upper right side of the spring 3. The wire locking device 13 of each sensor is mounted facing the spring 3, i.e., located inside each sensor, to ensure that the wire is connected to the spring 3 via the shortest path and the smallest angle, further ensuring that the force is transmitted in a straight line. The wire locking device 13 of each force sensing module is connected to the lower end of the spring 3 via an independent wire. Pulling the wire applies tension to the spring 3, and the force value is displayed in real time on the digital display panel 5. The spatial arrangement of the three force sensors ensures that their force-applying ends (i.e., the wire outlet of the wire locking device 13) are coplanar with the vertical centerline of the spring 3. Therefore, when the cord is stretched through the locking device 13, the direction of the applied tension is consistent with the axial direction of the spring 3, and all forces act on the same straight line. This fundamentally ensures that regardless of whether forces are applied in the same or opposite direction, their lines of action coincide with the center line of the spring 3, eliminating the non-collinearity error caused by the instrument thickness in traditional solutions. The digital display panel 5 is fixed in an easily observable position on the panel, and it is equipped with a power switch 51 and a zero-adjustment button 52 for controlling the power supply and performing zero-point calibration before measurement to ensure accurate readings.

[0034] The laser marking module is used to precisely mark and reproduce the deformation position of spring 3 to achieve the determination of "equivalent substitution". The laser marking module includes a laser pointer 10 and an optical fiber. The laser pointer 10 is mounted on a metal track 6 via a positioning slider 9. The metal track 6 is fixed to the display panel 1 by screws parallel to the tension direction of spring 3. The positioning slider 9 has a groove on its inner side that matches the cross-section of the track, allowing it to smoothly fit onto the track. The tension-adjusting bolt 11 is screwed in from the side of the slider, and its end can press against the side of the metal track 6, achieving positioning through friction. This structure allows the user to easily and smoothly move the laser pointer 10 to the desired position, and then securely lock it by tightening the bolt 11, making the operation extremely convenient and stable.

[0035] The working principle of the laser marking module is as follows: When spring 3 is stretched to a certain deformation position, the position of laser pointer 10 is slid and adjusted so that the laser beam accurately enters the end face of the optical fiber. At this time, due to the principle of total internal reflection, the optical fiber will be fully illuminated, and this optical path is the "optical mark" of the current deformation position of spring 3. When the component force is removed and the resultant force is used to pull spring 3, the magnitude of the resultant force is slowly adjusted until the optical fiber is fully illuminated to the same brightness again, indicating that spring 3 has returned to the exact same deformation position. At this time, the effect of the resultant force is equivalent to that of the two component forces before. This optical marking method greatly reduces the parallax when the human eye observes the marked point, and significantly improves the accuracy and visualization effect of the experiment.

[0036] The cable locking device 13 used in this invention is a one-way cable locking device. It has an internal ratchet or friction plate structure, allowing the cable to move smoothly in the pulling direction, but can lock in the opposite direction to prevent the cable from retracting. This design allows the experimenter to release the cable after stretching the spring 3, while the pulling force remains relatively stable through the self-locking function of the cable locking device 13. This facilitates easy and accurate reading of the force value on the digital display 5, effectively overcoming the difficulty in reading the value caused by shaking when the cable is pulled directly by hand.

[0037] The display panel 1 is preferably a transparent acrylic sheet. Multiple sets of mounting holes are pre-set on the display panel 1. These holes correspond to the mounting holes on components such as corner brackets, metal tracks 6, and tee-hole connecting blocks 8, and are connected using standard fasteners such as screws and nuts. This modular opening design allows the positions of each component to be flexibly adjusted according to teaching needs, enhancing the versatility and reconfigurability of the device.

[0038] The working principle of this utility model is as follows: For the synthesis of two forces in the same direction, the spring 3 is first stretched by applying a component force in the same direction using the first force sensor 4a and the second force sensor 4b. The optical fiber is then illuminated by moving the laser pointer 10 to mark the deformation position and record the component force data. Then the component force is removed, and the spring 3 is stretched again to the same position where the optical fiber is illuminated by a single pulling force. The resultant force at this time is recorded, and the data analysis concludes that the magnitude of the resultant force is the sum of the two component forces. For the synthesis of two forces in opposite directions, the process is similar. By applying component forces in opposite directions and finding the equivalent resultant force, the magnitude of the resultant force is finally concluded to be the difference between the two component forces.

[0039] The above description provides examples of the preferred embodiments of this utility model. Any aspects not detailed herein are common knowledge to those skilled in the art. The scope of protection of this utility model is determined by the claims. Any equivalent modifications based on the technical teachings of this utility model are also within the scope of protection of this utility model.

Claims

1. A demonstration apparatus for the synthesis of two forces along the same straight line, characterized in that, include: Display panel (1), on which a power module (2) is provided; Spring (3) is vertically fixed to the display panel (1) and is used to visually display the effect of force through deformation; The force sensing module includes at least three force sensors and a digital display board (5) corresponding to each force sensor. Each force sensor is fixed to the display panel (1) by a corner bracket. A wire lock (13) is fixed to the force sensor by a conversion connector (12). The digital display board (5) is disposed on the surface of the display panel (1) and is provided with a switch button (51) and a zeroing button (52). The laser marking module includes a laser pointer (10) and an optical fiber. The optical fiber is fixed to the lower end of the spring (3). The laser pointer (10) is slidably disposed on the display panel (1). The laser pointer (10) is used to irradiate the optical fiber to mark the deformation position of the spring (3) during the sliding process. Each of the wire locking devices (13) is connected to the lower end of the spring (3) via a wire, and the force-applying end of each of the force sensors is coplanar with the center line of the spring (3) to ensure that the force applied to the spring (3) is on the same straight line.

2. The demonstration apparatus for the synthesis of two forces on the same straight line according to claim 1, characterized in that, The force sensors are in the form of three, including a first force sensor (4a), a second force sensor (4b), and a third force sensor (4c).

3. The demonstration apparatus for the synthesis of two forces on the same straight line according to claim 2, characterized in that, The first force sensor (4a) is located on the lower left side of the spring (3), the second force sensor (4b) is located on the lower right side of the spring (3), and the third force sensor (4c) is located on the upper right side of the spring (3). Each of the locking devices (13) is located at one end close to the spring (3).

4. The demonstration apparatus for the synthesis of two forces on the same straight line according to claim 1, characterized in that, The laser pointer (10) is mounted on the metal track (6) via a positioning slider (9). The metal track (6) is fixed to the surface of the display panel (1). The positioning slider (9) is provided with bolts (11) for adjusting the tightness.

5. The demonstration apparatus for the synthesis of two forces on the same straight line according to claim 1, characterized in that, The optical fiber is fixed to the lower hook of the spring (3) by an optical fiber corner bracket (14), and the upper end of the spring (3) is connected to the three-way hole connecting block (8) through a metal sheet (7) with a hole in the middle and fixed to the display panel (1).

6. The demonstration apparatus for the synthesis of two forces on the same straight line according to claim 1, characterized in that, The locking device (13) is a one-way locking device used to lock the rope during the experiment.

7. The demonstration apparatus for the synthesis of two forces on the same straight line according to claim 1, characterized in that, The display panel (1) is an acrylic sheet with multiple sets of mounting holes on its surface for fixing various module components.

Images