JPH0414235Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to a blackboard compass that draws a circle on a display portion of a blackboard, whiteboard, or the like.

[Prior art and problems]

Conventionally, a compass used to draw a circle on a blackboard consisted of two sticks, one of which had a needle or a rubber foot, and the other end of which held a chalk or water-based felt pen. something is widely known,
Used in schools, etc.

However, conventional compasses configured as described above have the drawback that, for example, if the needle is attached to the tip of the foot that serves as the axis of rotation, needle marks will remain on the board surface and may damage the board surface. It was hot.

Furthermore, scratches on the board surface can be caused by chalk or water-based ink accumulating.
Gradually, it became difficult to see the blackboard.

Also, if the rotating shaft has a rubber tip, the tip rotates and rubs against the blackboard surface.
The number of rubber marks left or rubbed on the board gradually increased, making the blackboard difficult to read and giving it an unclean feel.

Further, the axis of rotation shifts during the operation of drawing a circle, resulting in the inconvenience that the beginning and end of the circle do not coincide.

Furthermore, the compass was large and difficult to handle, and the opening angle of the legs could be inadvertently changed during rotation, sometimes causing the starting and ending points of the circle to not match.

In addition, since the compass was set perpendicular to the board surface, it was necessary to keep the axis in contact with the board while sliding the chalk or felt pen, which required a great deal of care.

[Purpose of invention]

In view of the above-mentioned drawbacks of the conventional art, the present invention aims to provide a blackboard compass that can easily draw a circle without damaging the blackboard surface.

[Key points of the idea]

According to the present invention, the above object is to connect a suction part with a suction means capable of suctioning to a board surface, an attachment means for attaching a blackboard writing instrument, and connect the suction part and the attachment means to the suction part. and a connecting means that can be rolled up and stored, and by pulling out the connecting means from the suction part to a required length, the length of the suction part and the attachment means is adjusted, and the writing instrument attached to the attachment means is This is achieved by providing a blackboard compass that is characterized by creating an arc by rotating around a suction part.

[Example of idea]

An embodiment of the present invention will be described in detail below with reference to the drawings. FIG. 1 is a sectional view of essential parts showing an embodiment of the present invention. In the figure, the blackboard compass is composed of a magnet 2 and a rotating shaft 3 of a housing 1 as an attraction means, a wire 4 as an arm member, and a ring 5 as a writing instrument attachment means.

The rotating shaft 3 is connected to the housing 1 by the head 3b and the collar 3a.
It is rotatably supported by the housing and will not fall out from the housing. Further, a locking hole 3c is bored in the upper part of the rotating shaft 3, and one end of the wire 4 is fastened thereto. Furthermore, a magnet 2 is fitted to the bottom surface of the housing 1.

On the other hand, a ring 5, which is a writing instrument attachment means, is fixed to the tip of the wire 4.

FIG. 2 shows another embodiment of the writing instrument attachment means. The writing instrument attaching means has a ring 5 and a wire winder 6 attached to the tip of the wire 4, and the wire winder 6 adjusts the radius of the circle drawn by adjusting the length of the wire 4 fed out. It has a lock mechanism that can be set arbitrarily.
While the lock button 7 is pressed, the wire can be unwound, and when the force for pulling the wire is stopped, the wire is stored in the wire winder. If you release your finger from the lock button 7, the length of the wire can be fixed at that point.

FIG. 3 shows another embodiment of the suction part in the present invention. The attraction means includes a bottom member in which a magnet 2a is fitted into the inner diameter of the bearing 8 and is integrated with the housing 1a, and the magnet 2a is fixed on the blackboard by the force of attraction to the magnetic material, and the housing 1a is fixed on the blackboard.
is configured to be rotatable integrally with the outer peripheral surface of the bearing 8. A wire winder 6a is fitted into a recess in the housing 1a, and a wire 4 serving as a connecting means is fed out from the wire winder 6a to the outside of the housing through a guide groove 9. These housing 1a, bearing 8, magnet 2
a. A suction section is constituted by the wire winder 6a. A mechanism (not shown) capable of winding up the wire using a spring in the winder and a wire lock button (not shown) allow the wire to be wound up by arbitrarily setting the length of the wire. This wire lock button (not shown) is extended above the housing surface and protrudes so that the radius can be set by operating the housing 1a.

FIG. 4 shows another embodiment of the writing instrument attachment means. The writing instrument attachment means is composed of a metal fitting 10 fixed to the tip of the wire 4 and a clip 11, and the metal fitting 10 has two holes 10a bored in the longitudinal direction of the wire 4. A hole 10a at the tip of the metal fitting 10 is engaged with a pin 12 of the clip 11.

With the above configuration, it is possible to draw a circle by holding a writing instrument in the clip 11, and
As shown in FIG. 7, by hooking the hole 10a of the metal fitting 10 onto a hook 13 erected at the end of the blackboard, the hook 13 can be used to draw a straight line on the blackboard surface with the clip 11 attached. Figure 8 shows the 7th
It is a side view of the main part of a figure.

FIG. 5 shows another embodiment of the blackboard compass of the present invention. In this embodiment, a compass is constructed using a scale 14 instead of the wire 4 as a connecting means. The blackboard compass is composed of a housing 1b as a suction means, a clip 11a as a writing instrument attachment means, a scale 14 as a connecting means, and a scale winding tool 15.

A pedestal 16 is attached to the housing 1b on a rotating shaft, and a scale winding tool 15 is fixed on the pedestal 16 so as to rotate together with the rotating shaft. Incidentally, the housing 1b, the pedestal 16, and the scale take-up tool 15 constitute a suction section. The scale winding tool 15 has a spring mechanism and a lock mechanism (not shown).By pressing a lock button 17, the scale 14 can be pulled out to any desired length, and by releasing the lock button, the scale can be pulled out to any desired length. Can be fixed at length. Furthermore, when using this type of scale, the radius must be set directly above the center of the rotation axis. Therefore, the scale winding tool 15 is fixed on a table with its winding center shifted from the axis to the opposite side of the scale pulling direction.

In this embodiment, the point at which the scale 14 emerges from the scale winder is directly above the center of the shaft, but in order to make it easier to read, it is moved to the opposite side of the direction in which the scale 14 emerges from the pedestal 16 and the scale winder. A reading indicator may be attached to the edge of the pedestal 16 at the bottom of the reading unit.

In this embodiment, because the clip 11a is attached to the tip of the scale, the reading on the scale does not match the radius of the circle drawn. That is, the radius of the circle is the value obtained by adding the distance from the tip of the scale to the approximate center of the clip 11a to the scale graduation. Therefore, in order to facilitate this calculation, the length of the clip 11a is set so that the distance from the scale tip or 0 cm index to the clip center is an integer. Furthermore, the scale may include the length to the center of the clip.

The clip 11a has a hole into which a writing instrument is inserted in order to facilitate the fixing and attachment/detachment of the writing instrument, and this hole has one end cut out along the insertion direction of the writing instrument. Furthermore, since it is formed of an elastic member, when a writing instrument is inserted, both ends of the notch expand slightly outward and the writing instrument is held down by the restoring force inward, thereby achieving the desired effect. Next, the relationship between the scale 14 and the clip 11a will be explained. While drawing a circle using a felt pen, if the clip 11a is tilted in a direction perpendicular to the direction of drawing out the scale, that is, if the pen is tilted in the circumferential direction with respect to the arc being drawn, there is no apparent problem; When the clip 11a is tilted with respect to the direction of drawing out the scale, that is, when the pen is tilted radially outward or inward with respect to the circumferential direction, the radius of the circle is substantially perpendicular to the blackboard surface. Since the radius will increase or decrease from the radius when it was , it often happens that the point at which the circle starts and ends does not match. This gives a large appearance of inconsistency and does not provide completeness of the circle in drawing, which affects the ease or difficulty of handling this type of drawing device (or device). Therefore, in this embodiment, as shown in FIG. 5, there is a convexly protruding joint 18 on the scale side of the clip 11a, and a joint 19 having the same shape as the above-mentioned joint is provided on the end of the scale 14 on the clip side. It is attached to the scale 14 integrally with the scale support member 20. A hole passing through the joints 18 and 19 in a direction perpendicular to the drawing direction of the scale 14 is made, and the two joints are joined by a pin 21.
At this time, the respective joining surfaces of the joining parts 18 and 19 are formed into a convex shape and a concave shape, and after being fitted, they are pinned. By configuring the joints 18 and 19 between the clip 11a and the scale 14 in this way, the clip 11a and the scale 14 near the joint are integrated, so when drawing a circle, the inclination of the pen in the radial direction will be reduced near the joint. Since it is greatly reduced, it is easy to handle and it is easy to match the starting point and ending point of the circle.

FIG. 6 is a perspective view showing another embodiment of the present invention. In the figure, the blackboard compass is composed of a fulcrum 22, a scale 23, and a clip 11b. The fulcrum stand 22 is equipped with a magnet (not shown) at the bottom and is configured to be fixed on the blackboard surface.

The scale 23 has a plate shape or a rod shape, is rotatably provided on the fulcrum stand 22, and is provided with a scale 23a.

Further, the clip guide 25 is inserted through the scale 23 and is configured to be fixed with screws 24. This clip guide 25 is fixed in accordance with an arbitrary scale value. The length of the screw 24 is
Since it is longer than the thickness of the clip guide 25, when screwed in, it reaches the scale member and presses against it, so the clip guide 25 supporting the screw is set to a desired scale value by this reaction. A clip guide 25, in which the clip 11b and a scale reading window 26 are integrally molded, is attached so as to be able to slide on the plate-shaped scale 23. A reading indicator 27 is provided in the scale reading window 26, and the reading indicators 27a and 27b are provided on an extension line from the center of the clip 11b.

By using a material that is resistant to twisting, such as a box-shaped member, for the scale member, twisting in the circumferential direction can also be removed, making it easier to draw a circle with higher precision.

In addition, the height of the rotation axis of the fulcrum table 22 is set at the clip 1.
If the size of the clip 11b is made higher than that of the blackboard, even when the clip 11b is rotated, the seat of the clip 11b will not shift toward the blackboard surface, and a smooth circle can be drawn.

Furthermore, the clip 11b or the clip guide 25
If a caster or roller is installed at the lower end of the pen so that the length of the pen inserted is the same as or slightly longer than the installation surface, the scale can be kept horizontally, smooth rotation can be obtained, and You can easily draw accurate circles. In such a configuration, a rotatable handle may be provided on the clip, the clip guide, or the tip of the scale.

In the above embodiments, a magnet was used as a suction means for the blackboard surface, but if a vacuum suction cup is used, it can also be used for a non-magnetic blackboard.

[Effect of idea]

As explained in detail above, according to the blackboard compass of the present invention, the pivot foot does not stain or damage the blackboard, and it is easy to operate because you only need to pay attention to the tip of the pen when drawing a circle. . Furthermore, since the radius can be set arbitrarily and the radius does not change while drawing, it is possible to draw a circle with high certainty.

Furthermore, the writing instrument can be easily removed, so you can quickly draw circles in different colors.

Moreover, it has the advantage that the storage form is not bulky and does not take up much space.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of essential parts showing one embodiment of the present invention, FIG. 2 is a perspective view showing another embodiment of the writing instrument attachment means of the present invention, and FIG. 3 is another suction suction device of the present invention. 4 is a perspective view showing another embodiment of the writing instrument attachment means, FIG. 5 is a perspective view showing another embodiment of the present invention, and FIG. 6 is a perspective view showing another embodiment of the writing instrument attachment means. FIG. 7 is a perspective view showing another embodiment of the present invention, FIG. 8 is a perspective view showing the state of use of the present invention, and FIG.
It is a side view of the main part. 1, 1a, 1b... Housing, 2, 2a...
Magnet, 3... Rotating shaft, 3a... Tsuba, 3b... Head, 3c... Locking hole, 4... Wire, 5... Ring, 6, 6a... Wire winder, 7... Lock Button, 8... Bearing, 9... Guide groove, 10...
Metal fittings, 10a... Holes, 11, 11a, 11b...
Clip, 12...Pin, 13...Hook, 14
...Scale, 15...Scale winder, 1
6...Pedestal, 17...Lock button, 18, 19...
Joint portion, 20...Support member, 21...Pin, 22
...Fulcrum stand, 23...Scale, 23a...Graduation, 24...Screw, 25...Clip guide, 2
6...Scale reading window, 27...Reading index.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A suction part equipped with a suction means capable of adsorption to a board surface, an attachment means for attaching a blackboard writing instrument, and a connection between the suction part and the attachment means,
and a connecting means that can be rolled up and stored in the suction part, and the length of the suction part and the attachment means can be adjusted by pulling out the connecting means to a required length from the suction part, and the connecting means can be attached to the attachment means. A compass for a blackboard, characterized in that an arc is created by rotating a writing instrument with the suction part as a center. (2) The blackboard compass according to claim 1, wherein the suction means is a magnet. (3) The blackboard compass according to claim 1, wherein the suction means is a vacuum suction cup.