DE10105400A1 - Demonstration device for physical principle of independence of movement demonstrates constant acceleration and composite motions so as to enable them to be observed in slower form - Google Patents

Abstract

The device demonstrates movements with constant acceleration and composite motions so as to enable them to be observed in slower form. Especially projected motions can be demonstrated using a quasi slow motion system. Free fall, steep projection and horizontal projection can be demonstrated using bodies (3,4) rolling or sliding on a plate (1).

Description

field of use

The invention relates to a device for demonstrating movements with constant acceleration and compound movements (skewed throw and horizontal throw) individually or simultaneously or in Connection with each other, in particular through the simultaneous Demonstration of an accelerated movement from rest (like Falling motion) and a parabolic motion (like throwing motion) the principle of independence of movements can be represented.  

State of the art

To demonstrate the physical "principle of independence of the Movements "is currently becoming the classic monkey shot in teaching" demonstrated.

This is essentially a "horizontal throw" of a Body (shot of a bullet) that coincides with a "free fall" of a other body (falling movement of a stuffed monkey) begins. The "limb" (Bullet) is accelerated precisely in the direction of the "falling body" (monkey). Regardless of distance and launch speed, the projectile hits the monkey and thus confirms the above physical principle.

The experimental setup can be described as follows:
A blowpipe is attached to a household ladder in such a way that when you look through it you have exactly one small monkey in sight. This monkey, in turn, hangs on a thread that is attached to a metal pin with a loop via 2 pulleys. This metal pin is attached just below the mouth of the blowpipe so that the thread runs directly in front of the mouth. If the bullet now leaves the blow tube when the shot is fired, the bullet pulls the loop off the metal pin when it flies out. The monkey starts its fall movement at the moment the bullet leaves the blowpipe.

Documentation by the German Patent and Trademark Office dated September 28, 2000 for first filing AZ 100 07 000.0:
Category A: General information on the state of the art, technological background
DE-GM 17 57 820
US 29 13 834
US 37 77 412
DE-OS 19 33 334
Product catalog natural sciences. Leybold Didactic GmbH, inc. 12. 3. 99, pp. 28, 29;
Main Catalog Physics Experiments, Leybold-Heraeus GmbH, Edition 1986, pp. 44, 45;
Physics main catalog P0490, Phywe, entered 7. 12. 88, pp. 46, 47.

Disadvantages of the prior art

• - The above Experiment setup requires very generous space Ratios, because if the distances are too short this demonstration will not looks very impressive.
• - The structure is extremely complex and labor intensive.
• - The adjustment is sensitive, which means that the test sequence in its Reproducibility is not reliable.
• - The rate of launch is insufficient to dose.
• - To a certain extent, the blowpipe also provides a hygienic one Problem there.
• - The most serious disadvantage, however, is that the attempt for the Eye runs too fast and therefore the movements themselves are hardly noticeable anymore.

Object of the invention

• - The object of the invention is a device for demonstrating Movements with constant acceleration and compound movements (skewed and horizontal Litter) individually or simultaneously or in connection with each other, in particular by the simultaneous demonstration of a accelerated movement from rest (like falling movement) and a parabolic movement (like throwing movement) the principle the independence of the movements can be demonstrated.
• - The course of these movements should be perceptible to the eye, enable the processes to be viewed in "slow motion", so to speak.
• - The launch angle and launch speed should be freely selectable his.
• - The device should be as small as possible enable large and clearly visible display.
• - The adjustment must not be sensitive to disturbances.
• - The handling should be simple and not very labor intensive.

Solution of the task

These tasks are performed by a device with the features of Claim 1 solved.  

Advantages of the invention

• - The motion sequences can be observed in "slow motion" become.
• - The angle of inclination "α" of the device can be adjusted by means of the adjusting screw ( 12 ; sketch 1). The acceleration g (= 9.81 ms ^-2 ) that occurs in free fall is significantly reduced to g.sin α with the device, so that falling movements can be observed in slow motion, so to speak.
• - The launch speed is good to dose.
• - The launch angle is adjustable.
• - The adjustment is easy to make and responds insensitive to disturbances.
• - The device is good even with minimal space applicable.
• - The movements can be on the device itself or in their projection using a daylight projector in silhouette strong magnification can be observed clearly.
• - The possibility of a foil printed with a grid at the same time projecting makes both the explanation and that easier Understanding the movements.
• - Structure and handling of the device are simple and with minimal effort.

The exemplary embodiment is shown in the schematic diagrams 1-4 and is described in more detail below [see schematic diagram 1]:
A rotatable aiming device ( 2 ) is attached to a PMMA plate ( 1 ) (hereinafter referred to as "Plexiglas"). This target device contains a launching device for a steel ball (hereinafter referred to as a projectile ball ( 3 )), which will be explained in more detail.

The aiming device is aligned with another steel ball (hereinafter referred to as the target ball ( 4 )) and fixed with the locking screw ( 5 ) after the alignment. The target ball is held in position by an electromagnet ( 6 ) when the electrical supply is switched on.

There are different mounting positions for the electromagnet (a-h) provided to make different launch angles possible. In which Position (h) fulfills a special task, which will be explained in more detail.

The launcher mounted on the aiming device consists of two guide rails ( 7 ) and a leaf spring ( 8 ) to be tensioned by hand, which accelerates the bullet along the guide rails in the direction of the target ball. [See also sketch 2] The projectile accelerated in this way passes a light barrier (photoelectric resistance) ( 9 ) when it leaves the guide rails, which interrupts the power supply to the electromagnet via an electronic circuit ( 10 ) and thus releases the target ball. [see also sketch 3]

The plexiglass plate stands on three studs, which are mounted in through threads. Thus, the plate can be used in an absolutely horizontal position using the adjusting screws ( 11 and 12 ) and in an inclined position using the adjusting screw ( 12 ). The angle of inclination can be freely selected within certain limits and is infinitely adjustable. If the electromagnet for positioning the target ball is attached in the mounting position (h), a horizontal shot, i.e. firing angle = 0 °, is possible. [see sketch 4]

For the manufacture of the device, this means that the imagined target line of the aiming device must be at a 90 ° angle to the direction of fall of the target ball. This must be observed during production. The limiting strips ( 13 ) prevent the balls from rolling away beyond the plexiglass plate edge. Photoelectric switch, electromagnet and electronic circuit are electrically connected to each other. Power is supplied via a power supply (9 V).

The entire device is made of clear plexiglass. This is necessary to create a transparent, projection-suitable surface, which enables a demonstration using a daylight projector.

The device has the approximate dimensions [mm] of: 360 × 290 (6 thick).

This exemplary embodiment offers numerous alternatives, which are listed below:

• - The plexiglass plate can be projected by any other Material to be replaced. A reflection is also conceivable. is a Projection is not a requirement, so many suitable ones come Materials into consideration.
• - The plexiglass plate can be printed with lines or a grid which is projected in use and the viewer making observation easier.

Alternative example

A device that implements the principle of the invention in a further developed manner is shown in the alternative embodiment [see schematic diagrams 5-10] and is described in more detail below [see schematic diagram 5]:
A launcher is rotatably mounted at one point on a PMMA plate ( 14 ) (hereinafter referred to as "Plexiglas"). The plexiglass plate stands on three studs, which are mounted in through threads. Thus, the plate can be used in an absolutely horizontal position using the adjusting screws ( 28 and 29 ) and in an inclined position using the adjusting screw ( 29 ). Here, the angle of inclination can be freely selected within certain limits and is infinitely adjustable.

The launching device is designed such that a steel ball ( 22 ) (hereinafter referred to as a projectile ball) is precisely aligned with a further steel ball ( 25 ) (hereinafter referred to as a target ball). The device enables the target ball to be released at the same time as the bullet accelerates.

The entire launching device can be used both in a horizontal position (horizontal throw) and, rotated continuously around the pivot point ( 17 ), in an inclined position (oblique throw) [see schematic diagram 6 ]. [Basic sketch 5 and basic sketch 7, detail E]

The carrier ( 15 ) of the launcher is rotatably mounted at point 17 ( 17 ) and clamped onto the plexiglass plate ( 14 ) with a knurled nut. The handle ( 18 ) pulls on the slide rod ( 16 ) mounted in the carrier, which tensions the compression spring ( 26 ) via the abutment ( 27 ). The abutment ( 27 ) can be steplessly positioned on the sliding rod and can be clamped using the clamping screw. This allows the spring to be preloaded, which enables adjustable launch speeds. The second abutment is the carrier. The sliding rod ( 16 ) is rigidly connected to a rotating part ( 20 ) via the connecting piece ( 19 ). Part 20 is guided in the carrier and can move contactlessly over the mandrel ( 21 ) by milling. When the device is cocked, this rotating part releases the mandrel ( 21 ) onto which the projectile ball ( 22 ) is attached.

[Basic sketch 5 and basic sketch 8, detail F]

Simultaneously, a pin ( 24 ) is guided through a through hole in the carrier via the slide rod ( 16 ) and connecting piece ( 23 ). When the device is cocked, the target ball ( 25 ) is placed on the pin ( 24 ). The shift rod, connecting piece and pin are rigidly connected to one another.

Letting go of the handle causes the spring to relax, and thus to Movement of the push rod and the rigidly connected to it Components.

Turned part 20 pushes the bullet from Dorn ( 21 ).

[see schematic diagram 7, detail E]

At the same time, pin ( 24 ) releases the target ball.

[Principle sketch 8, detail F]

Similar to "throwing" and "falling movement" projectile and target ball roll up the plexiglass plate.

The functional process is shown in the sketches 9 and 10:
Alignment of horizontal throw "[see sketch 9]
Alignment "lopsided throw" [see sketch 10]

The base plate of the device is made of clear plexiglass. This is necessary to create a transparent, projection-suitable surface, which enables a demonstration using a daylight projector.  

A component must be provided on the launcher itself, which the Allows attachment to a bracket. So is the launcher can be used regardless of their base plate to move in To demonstrate "real time", so do not roll the balls on the plane an actual litter or case is to be demonstrated.

The device has the approximate dimensions [mm] of: 360 × 300 × 80.

List of reference symbols for the schematic diagrams 1-4

1

PMMA (plexiglass) plate

2nd

Aiming device (rotatable)

3rd

Projectile ball (steel ball)

4

Target ball (steel ball)

5

Locking screw (countersunk screw)

6

Electromagnet

7

Guide rails

8th

Leaf spring

9

photoelectric resistance

10th

electronic switch

11

/

12th

Adjusting screws (studs)

13

Boundary strips (L-profile)
ah mounting positions for electromagnet

List of reference symbols for schematic diagram 5-10

14

Plexiglass plate

15

carrier

16

Sliding bar

17th

Pivot point (clamping screw)

18th

Handle

19th

Connecting piece (sliding rod / rotating part)

20th

Turned part (launch)

21

Thorn (bullet)

22

Bullet

23

Connection piece (push rod / pin)

24th

Pen (target ball)

25th

Target ball

26

feather

27

Abutment (spring)

28

/

29

Adjusting screws

Explanation of symbols for sketches 1-4

1

PMMA (plexiglass) plate

2nd

Aiming device (rotatable)

3rd

Projectile ball (steel ball)

4

Target ball (steel ball)

5

Locking screw (countersunk screw)

6

Electromagnet

7

Guide rails

8th

Leaf spring

9

photoelectric resistance

10th

electronic switch

11

/

12th

Adjusting screws (studs)

13

Boundary strips (L-profile)
ah mounting positions for electromagnet

Explanation of symbols for outline sketch 5

j rail (suspension)
k target ball
l electromagnet
m clamping device
n pipe (launch)
o bullet
p compression spring
r suspension
s washer (spring abutment)
t pull rod
u handle
v Photoelectric resistance (light barrier)

Claims (5)

1.Device for demonstrating movements with constant acceleration and compound movements (oblique throw and horizontal throw) individually or simultaneously or in connection with one another, in particular by simultaneously demonstrating an accelerated movement from rest (such as falling movement) and a parabolic movement ( like throwing movement) the principle of independence of the movements can be represented, characterized in that the movements can be observed in a slowed-down form. 2. Device according to claim 1, characterized in that especially throwing movements are demonstrated in "slow motion" can. 3. Device according to claim 1, characterized in that the movement of the "free fall", the "lopsided throw" and the "horizontal Throws "represented by bodies rolling or sliding on a plate become. 4. The device according to claim 1, characterized in that in the process, the movements using a daylight projector or a punctiform light source on a projection surface in the silhouette can be displayed. 5. The device according to claim 1, characterized in that the "free fall", "slanted or horizontal throw" by means of the same Device can be demonstrated in "real time".