JPS591238Y2 - Experimental pulley equipment - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a pulley that can be fixed to a steel blackboard by the action of a magnet, and is used for experiments such as the balance of forces.

Conventionally, this type of instrument focuses on the fact that by measuring the extension of a spring, the magnitude of the force acting on the spring can be determined. There was one that made it possible to fix the ends with pins, pull the springs in each direction, and measure the elongation of each spring when they balanced out.

However, since experiments using this spring are placed on a desk, it is difficult to conduct experiments with a small number of students, and when a teacher uses a blackboard to explain the balance of forces. It is not suitable as a device for showing students experiments to support their explanations, and it requires measuring the elongation of the spring in order to find out the magnitude of the force. It took a long time to create a sense of balance.

In view of these circumstances, this project devised a device that could use a pulley on a blackboard, making it possible to experiment with the balance of forces using the pulley, thereby eliminating the aforementioned deficiencies. It is.

The actual wearable pulley device according to the present application will be explained in detail below.The structure consists of a hook portion 1 for hanging on the upper edge of a steel blackboard 10, a main body 3 on which a pulley 2 is pivoted, and a pulley device on the back side of the main body. is characterized by comprising a magnet portion 4 magnetically attached to the blackboard.

Next, the present invention will be further explained based on illustrated embodiments.

Figure 1 is a side view of the proposed pulley device, in which the pulley 2 is pivoted on a U-shaped metal fitting 3A with one side long, the hook portion 1 is L-shaped, and the magnet portion 4 is a yoke with a magnet sandwiched between them. A so-called magnetic catcher type with 4A protruding outward is used.

In the figure, reference numeral 5 denotes a thumbscrew for screwing the U-shaped metal fitting 3A on which the pulley is pivoted onto the main body 3, and the mounting position of the metal fitting 3A can be adjusted up and down.

Next, FIG. 2 is a diagram showing a state in which an experiment on the balance of three forces is being conducted using the pulley device of the present invention.

In the figure, 11 indicates a thread, and 12 indicates a weight.

In the illustrated case, the tension of a string with three weights tied to one end is changed in direction by a pulley 2 and acts on a fulcrum 13.

The tension of the string with four weights tied to the other end is changed in direction by the pulley 2' and acts on the fulcrum 13.

The fulcrum is then pulled downward by a string with five weights tied together.

At this time, the forces acting on the string are balanced, as can be easily seen from the vector composition of the forces, and the angles exerted by the string on both pulleys are right angles.

As mentioned above, two of the pulley devices of the present invention are used when conducting an experiment on the balance of three forces, but it is also possible to experiment with the action of the pulley itself. The number, shape, etc. of pulleys are not particularly limited to those shown in the drawings.

The structure of the pulley device according to the present application is as described above, and the structure provides the following specific effects.

That is, since the present invention is used by hanging it on the upper edge of a steel blackboard and attaching the magnet to the surface of the blackboard, it is possible to experiment three-dimensionally on the blackboard and make it look like a large number of people.

Therefore, the teacher can give explanations while experimenting on the blackboard, thereby promoting students' understanding.

Also, compared to conventional methods that use springs, the magnitude of the force can be measured by the number of weights tied to the string, which is obvious at a glance, and from this point of view it is also useful for students' understanding.

In addition, the pulley device of the present invention has high utility as a teaching tool because it allows various experiments to be performed three-dimensionally using the pulley itself.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, with FIG. 1 being a side view and FIG. 2 being a usage state diagram. 1... Hook, 2... Pulley, 3...
...Main body, 4...Magnet part, 10...Steel blackboard.

Claims (1)

[Scope of utility model registration request] A pulley device for experiment consisting of a hook part 1 for hanging on the upper edge of a steel blackboard 10, a main body 3 on which a pulley 2 is pivoted, and a magnet part 4 installed on the back side of the main body to be magnetically attached to the blackboard. .