FR2805645A1 - Pedagogical equipment for study of the pendular motion comprises a vertical plate with angular scale on the edge, a wire is fixed on a drum, going through a hollow guide and having an hook to attach a chosen weight - Google Patents

Abstract

Equipment comprises a vertical plate (10) with angular scale on the edge, a wire drum (20) and a wire guide (30) mounted on the plate. The wire is fixed on the drum, goes through the hollow guide (32) and has an hook (40) attached to its free end. The hook can link the wire (50) to a chosen weight (100).

Description

The present invention relates to an experimentation device for educational purposes for the study of pendular movements.

There are already such devices used in colleges or high schools, only consist of a vertical plate through which a thread at the end of which is hung a weight. However, it is not expected to be able to easily vary the parameters of the pendulum, that is to say the length of wire separating attachment point of the center of gravity of the suspended weight, and possibly also the weight hooked. To vary the length of the wire, it is sufficient to pull on the latter behind the plate, to increase the weight, and shorten the length of wire, to observe that the oscillation period decreases with the wire length. .

There is therefore a need to produce an experimentation device for educational purposes which is better adapted to a precise and exhaustive study of the pendular movements, in particular by allowing easy and reliable measurements.

The object of the invention is therefore to provide an experimentation device for educational purposes intended for the study of pendular movements, the structure of which is capable of varying the parameters of the pendulum, in an easy and precise manner, in order to a global study of pendular movements.

This problem is solved according to the invention, by means of an experiment device comprising: a fixed platen extending in a vertical plane and bearing on the front face angular graduations from the vertical; a winder of wire mounted rotating on the front face of the plate, said winder having a cylindrical drum and a rotating knob; a wire guide fixedly mounted on the front face of the plate, said wire guide being made in the form of a hollow element having a wire exit opening which is at a distance from the plane of said plate; and - a hook for connecting a wire, which is wound on the drum of the winder and out of the wire guide through the outlet opening thereof, at a weight selected in a set of weights.

The wire winder makes it easy to vary the length of the pendulum precisely and to measure the consecutive variations of oscillation angles of the pendulum.

Preferably, the wire winder is clipped onto the plate, and this wire winder is equipped with a pawl cooperating with a notch of the plate, for detecting the rotation of a lathe of said winder. The operator thus easily detects, by the noise of the passage of the notch, that he has made a full turn of the wheel, and he easily deduces the corresponding variation in the length of wire constituting the length of the pendulum.

Advantageously, the wire guide comprises a support ring and a hollow cone pierced at its base for the passage of the wire that emerges from its outlet opening. Preferably, the wire guide is clipped onto the plate, and its angular position is fixed by indexing. then it will be interesting to provide that the outlet opening of the wire guide is triangular in shape with a downward pointing point. This ensures a perfect positioning of the wire output of the wire guide, which conditions the exact verticality of the pendulum system in the initial state and stability during oscillation.

Advantageously, the hook is in the form of an elongate finger whose head allows hooking of the wire, and whose lower end has snap teeth for mounting or dismounting quickly a weight with a central bore adapted. Preferably, the platinum is in the form

of a <SEP> quadrant <SEP> in <SEP> quarter <SEP> of <SEP> circle, <SEP> and <SEP> it <SEP> presents <SEP> a
<tb> fingerprint <SEP> to <SEP> the <SEP> vertical <SEP> of the <SEP> wire guide, <SEP> serving <SEP> to <SEP> receiving
<tb> a <SEP> corresponding <SEP> portion <SEP> of the <SEP> hook <SEP> for <SEP> calibrate <SEP>
<tb> length <SEP> of <SEP> thread <SEP> in <SEP> start <SEP> of <SEP> manipulation.
<tb> On <SEP> can <SEP> also <SEP> predict <SEP> that <SEP> the <SEP> platter <SEP> is
<tb> equipped <SEP> superiorly <SEP> of a <SEP> rack <SEP> constituted <SEP> of <SEP> fingers
<tb> similar <SEP> to the <SEP> finger <SEP> forming <SEP> the <SEP> hook, <SEP> and <SEP> serving <SEP> to
<tb> receive <SEP> the <SEP> other <SEP> weights <SEP> of the <SEP><SEP> set of <SEP> weights.
<tb> Other <SEP> features <SEP> and <SEP><SEP> benefits of
<tb> the invention <SEP> will appear <SEP> more <SEP> clearly <SEP> at <SEP> the <SEP> light <SEP> of <SEP> la
<tb> description <SEP> which <SEP> goes <SEP> follow <SEP> and <SEP> of <SEP> drawings <SEP> appended,
<tb> for <SEP> a <SEP><SEP> mode of <SEP> particular <SEP> realization, <SEP> in <SEP> reference
<tb> to <SEP> figures <SEP> where
<tb> the <SEP> figure <SEP> 1 <SEP> is <SEP> a <SEP><SEP> view in <SEP><SEP> elevation of a
<tb><SEP> experiment <SEP> device for <SEP> to <SEP><SEP> study
<tb> pendular <SEP> motions <SEP> compliant <SEP> to <SEP> the invention <SEP>;
<tb> the <SEP> figure <SEP> 2 <SEP> is <SEP> a <SEP><SEP> view in <SEP><SEP> perspective illustrating
<tb> the <SEP> platter <SEP> of the <SEP> device <SEP> previous <SEP>;
<tb> - <SEP> the <SEP> figures <SEP> 3, <SEP> 4 <SEP> and <SEP> 5 <SEP> are <SEP> various <SEP><SEP> views of
<tb> the <SEP>reel> of <SEP> thread <SEP> when <SEP> is <SEP> disassembled <SEP> of <SEP> platinum
<tb> above <SEP>;
<tb> - <SEP> The <SEP> figures <SEP> 6 <SEP> and <SEP> 7 <SEP> are <SEP><SEP> views <SEP> in <SEP> perspective
<tb> of the <SEP> thread guide <SEP> equipping <SEP> the <SEP> Platen <SEP> above, <SEP> and <SEP> figure <SEP> 8
<tb> is <SEP> a <SEP> half <SEP> cut <SEP> of <SEP> this <SEP> component <SEP>;
<tb> - <SEP><SEP> Figure <SEP> 9 <SEP> is <SEP> a <SEP> cut <SEP> of <SEP> detail <SEP> of <SEP> the <SEP> tip
SEP><SEP> endpoint <SEP> showing <SEP> to <SEP> plus <SEP> large <SEP>
<tb><SEP> form <SEP> of <SEP> opening <SEP> of <SEP> output <SEP> of said <SEP> thread guide <SEP>;
<tb><SEP> figures <SEP> 10 <SEP> and <SEP> 11 <SEP> illustrate <SEP> in <SEP> perspective <SEP>
<tb> hook <SEP> serving <SEP> to <SEP> connect <SEP> the <SEP> thread <SEP> of the <SEP> pendulum <SEP> to <SEP> a <SEP> weight
<tb> determines.
<tb> The <SEP> figure <SEP> 1 <SEP> shows <SEP> a <SEP> experiment <SEP> device
<tb> to <SEP> purpose <SEP> educational <SEP> according to <SEP> the invention, <SEP> noted <SEP> 1, <SEP> which <SEP> is
<tb> intended <SEP> to <SEP> the <SEP> study of <SEP> pendular <SEP> motions.
<tb> This <SEP> device <SEP> has <SEP> a <SEP> platinum <SEP> fixed <SEP> 10
<tb> extending <SEP> in <SEP> a <SEP> plane <SEP> vertical <SEP> and <SEP> carrying <SEP> in <SEP> face <SEP> before 11 angular graduations 16 from the vertical, direction noted Z. The fixed plate 10 is supported by a column 12 extending vertically from a solid support plate 13, said column passing in two rear cradles 14, the shape of which is better visible in the perspective view of FIG. fixed. The plate 10 is fixed to the desired height by means of a knurled screw 15, whose head projects from the front face of the plate 10, and whose end bears on the small column 12.

There is provided a wire winder noted 20 rotatably mounted on the front face of the plate 10. wire winder 20 has a cylindrical drum 21 on which are wound several turns of a wire 50 whose end is attached to an internal protrusion 25 Part of the reel 20. The reel 20 also has a rotating knob for rotating the reel in one direction or the other to increase or decrease the reel. the length of the pendulum.

The structure of the reel 20 will be better understood with reference to FIGS. 3 to 5. It can be seen that the wire reel 20 has, beyond its cylindrical part constituting the drum 21, which is pierced by a notch passing -fil 24, latching lugs 22 for clipping the wire winder 20 on the plate 10. The axial space between the free edge of the drum 21 and the latching stop edges of the latching lugs 22 corresponds to the thickness of the plate 10. Thus, the wire winder 20 is held in place on the fixed plate 10, being able to rotate about its axis. FIG. 5 also makes it possible to distinguish the internally projecting tab mentioned above, which serves to attach the end of the wire which is then passed into the slot 24 and wound in several turns on the cylindrical drum 21.

There is further provided here, at the level of the latching lugs 22, a tongue 26 having an outward protruding protrusion 27 intended to form a pawl cooperating with a corresponding notch (not visible in Figures 1 and 2) of the passing through associated with the fixed plate 10. The pawl 26,27 thus cooperates with a notch of the plate 10, and allows to detect the rotation of a complete turn of the winder of the wire 20. Thus, during handling it is easy to identify with the noise corresponding to the passage of a notch, to find out how many turns the wire winder 20 has rotated, and thus to easily deduce the variation in the length of the wire thanks to an adequate choice of the diameter of the drum, for example 31.8 millimeters to ensure that a complete turn of the wire winder 20 corresponds to a change in wire length of 0.1 meter.

The experiment device according to the invention further comprises a wire guide 30 which is fixedly mounted on the front face of the plate 10. The wire guide 30 is designed as a hollow element having an exit opening of 34, which is at a distance from the plane of the plate 10. As can be seen more clearly in FIG. 2, and also in the specific views of FIGS. 6 to 9, the wire guide 30 comprises in this case a crown of support 31, intended to come into contact with the front face 11 of the plate 10, and a hollow cone 32, which is pierced at its base with an opening 33 for the passage of the wire 50. At its top, the hollow cone 32 has an outlet opening 34 through which the wire 50, as illustrated in FIG. 2, comes out. It is important to ensure that the wire 50 is perfectly positioned relative to its point of suspension, and remains stable during oscillations. of the pendulum. For this, it is arranged to fix the wire guide 3C so that its axis, which is perpendicular to the plane of the plate 10, is on the same horizontal as the tangent to the cylindrical winding drum 20 of the winder In addition, it is interesting to choose a particular geometry of the outlet opening 34, which geometry is illustrated in the detail view of FIG. 9: the outlet opening 34 of the wire guide 30 is indeed triangular shape tip downwards, which ensures a perfect stabilization of the wire both at the beginning of manipulation and during oscillation of the pendulum.

In FIGS. 6 to 8, there are also clipping tabs for clipping the wire guide 30 on the plate 10. As before, the distance between the inner face of the bearing ring 31 and the edge of attachment of the latching lugs 35 corresponds substantially to the thickness of the plate 10. It is also advantageous to provide that the position. angle of the wire guide about its axis is determined accurately. Indeed, since it is desired that the outlet opening 34 has a central tip facing downwards, it is important to properly position the wire guide on the plate 10, so that its angular position is determined accurately. this is achieved by ur: angular indexing, obtained by providing, as is visible in Figure 7, a projection 36 of a tongue which is similar to that provided to form the ratchet of the wire winder 20. In this In this case, the through passage of the plate 10 receiving the detent tabs 35 of the wire guide 30 has a notch, so that the wire guide 30 is in the desired angular position.

FIGS. 10 and 11 allow a better understanding of the particular structure chosen in this case for the hook 40 which makes it possible to connect the wire 50, wound on the drum 21 of the winder 20 and coming out of the wire guide 30 through the opening output 34 thereof, at a weight 10C selected in a set of weights <B> 100,101,102,103. </ B>

It is found that the hook is indeed in the form of an elongate finger 40 whose head 41 allows the attachment of the wire 50 through a passage opening 42. The lower end of the elongate finger 40 has teeth snap 44 on either side of a central slot 45, so that one can mount or dismount a central bore weight. Each weight of the experimental device has in fact a central bore whose diameter corresponds to that of the central portion 43 of the hook 40. The height of each weight will preferably be chosen such that the weight is maintained between the conical shoulders defining axially the central part 43.

As can be seen in FIG. 2, it can be seen that the plate 10 has an imprint 17 perpendicular to the outlet of the wire guide 30. this impression serves to receive the corresponding portion, which is other than the head 41, of the hook 40, to calibrate the length of the thread at the beginning of manipulation, as is shown in phantom in FIG.

We also see in Figure 1, the presence of a rack 18 equipping the upper plate 10. This rack 18 is preferably constituted as shown here by fingers 19 which are similar to the aforementioned finger 40 forming the hook. These fingers 19 are used to receive the other weights 101,102,103 of the game of weight, which also ensures that before storage of the device, all the weights are in place.

Preferably, as illustrated in FIGS. 1 and 2, the plate 10 is in the form of a quadrant quadrant. We could have provided a platinum in a semicircle, with graduations on either side of the vertical Z, but this brings nothing more to the more compact realization provided here.

Before manipulation, the operator passes the end of the wire 50 through the bore 33 of the wire guide 30 and the associated outlet opening 34 while operating the knob 23 of the wire winder 20. It then continues to unwinding the wire 50 by rotating the wire winder 20 in the corresponding direction, to bring the head 41 of the hook in the associated footprint 17 of the plate 10. It is then arranged for the wire winder 20 either on one notch in the corresponding position. He then fixes the hook 40 at the free end of the wire.

It then suffices, for carrying out an experimental manipulation, to manipulate the wire winder in order to choose the desired length of the pendulum, after having hooked a weight 100 by passing the hook 40 through the central bore 100.1 of said weight. We can then measure the oscillations of the pendulum, identify 1 maximum oscillation angle on the graduations 16 of the plate 10.

The operator can then vary pendulum length, preferably in successive notches, in one direction or the other. He can then directly check the well-known formula giving the pendulum period as a function of length, namely T = 71 '(1 / g). It is recalled, however, that this formula actually corresponds to an approximation which is valid for relatively low oscillation angles, in particular less than about 8.

The operator can also change weight by putting another weight on the hook 40. then finds that the period of the pendulum remains unchanged if the length of wire is not changed.

This has led to the realization of an experimentation device for pedagogical purposes, allowing a precise study of pendular movements. The structure of the experiment device according to the invention makes it possible to easily vary the parameters of the pendulum, in particular the length and the mass. Finally, the platinum of the experimental device is clearly visible at a distance of 1 apparatus, which allows a very demonstrative experimentation for a set of students.

The invention is not limited mode embodiment that has just been described, but on the contrary covers any variant using, with equivalent means, the essential characteristics stated above.

Claims (1)

A teaching device for educational purposes intended for the study of pendular movements, characterized in that it comprises a fixed plate extending vertically and carrying on the front face ) angular graduations from the vertical; a wire winder (20) rotatably mounted in front of the plate (10), said winder having a cylindrical drum (21) and a knob (23) for rotating; a wire guide (30) mounted on the front face of the plate (10), said wire guide being in the form of a hollow element (32) having a wire exit opening (34) which is at a distance from the plane of said platen; and - a hook (40) for connecting a (50), which is wound on the drum (21) of the reel (20) and out of the wire guide (30) through the outlet opening (34) of this one, at a weight (100) selected in a game weight (100,101,102,103). 2. Device according to claim 1, characterized in that the wire winder (20) is clipped on the plate (10). 3. Device according to claim 1 or claim 2, characterized in that the wire winder (20) is equipped with a pawl (26,27) cooperating with a notch of the plate (10), for detecting the rotation of a turn of said winder. 4. Device according to one of claims 1 to 3, characterized in that the wire guide (30) comprises a bearing ring (31) and a hollow cone (32) pierced at its base for the passage of the wire ( 50) which comes out of its outlet opening (34). 5. Device according to claim 4, characterized in that the wire guide (30) is clipped on the plate (10), and its angular position is fixed by indexing. 6. Device according to claim 4 and claim 5, characterized in that the outlet opening (34) of the wire guide (30) is triangular in shape with a downward pointing point. 7. Device according to one of claims 1 to 6, characterized in that the hook is in the form of an elongate finger (40) whose head () allows the attachment of the wire (50), and whose lower end has snap teeth (44) for quickly mounting or dismounting a suitable center bore weight. 8. Device according to one of claims 1 to 7, characterized in that the plate (10) is in the form of a quadrant quadrant. 9. Device according to claim 8, characterized in that the plate (10) has a footprint (17) at the vertical of the output of the wire guide (30) for receiving a corresponding portion (41) of the hook (40) for calibrate the length of the wire at the beginning of the operation. 10. Device according to claim 8 or claim 9, characterized in that the plate (10) is equipped superiorly with a rack (18) consisting of fingers 19) similar to the finger (40) forming the hook, and serving to receive the other weights (101,102,103) of the game of weight.