CN202847250U

CN202847250U - Magnetic teaching compasses

Info

Publication number: CN202847250U
Application number: CN 201220508255
Authority: CN
Inventors: 王德湘
Original assignee: Individual
Current assignee: Individual
Priority date: 2012-09-30
Filing date: 2012-09-30
Publication date: 2013-04-03
Anticipated expiration: 2022-09-30

Abstract

The utility model discloses magnetic teaching compasses which comprise a piece of strong annular magnet used for fixing and a cylindrical structure provided with two metal rotating arms. Scales are arranged on the metal arms, chalk sleeves are arranged under one ends of the metal arms, holes are formed on two sides and at two ends of the cylindrical structure, an inner thread and a matched screw are arranged at the upper portion of the structure, the threading screw can fix the metal arms, a plastic chalk sleeve which is the same as the sleeves under the tail ends of the metal arms is arranged at the lower end of the cylindrical structure, the plastic chalk sleeve is sleeved through a rubber band for inserting and fixing chalk, the cylindrical structure is inserted into a round hole of the annular magnet, and a circle with a required size can be drawn on a blackboard with a single hand by rotating the cylindrical structure. When lengths of the metal arms are not equal, two concentric circles can be drawn at one time. The magnetic teaching compasses have the advantages of being simple in structure, low in cost and suitable for being used on blackboards of various metal materials, and enables a user to draw a circle with known radial or the concentric circle with the single hand.

Description

A kind of magnetic compasses for teaching

Technical field

A kind of magnetic compasses in being applied to impart knowledge to students.

Background technology

Along with the development in epoch, teaching equipment is constantly upgraded, and nowadays, what general school all used is zinc-plated blackboard, i.e. the steel plate of plating zinc on surface, and this has brought new thinking for other teaching equipment ground renewals.In mathematical education, often to use compasses, mostly the compasses of usefulness are two legs shape structure now, it is the metal tip below the one leg, it is cylindrical shape below another, chalk can be inserted in the inside, with the time need two hands to cooperate to rotate compasses to draw circle at blackboard to come, cooperate slightly the bad metal tip that will occur to slip and cause picture to be justified unsuccessfully, and the metal tip can stay cut one at blackboard, of a specified duration will damage blackboard.Someone once designed with magnet fixedly the one leg of compasses come picture circle, be the invention of 200920077631.8 and 01206991.4 utility model such as the patent No.; Also there is the people once to design with line and comes the picture circle as turning arm, these design limitations are in the compasses mentality of designing of two legs structure, do not take full advantage of magnet to the suction function of metal, and the compasses of prior art design need two hand compounding practices could draw circle, use inconvenience, more can not disposablely draw two concentric circles.

Summary of the invention

For above-mentioned the deficiencies in the prior art part, the utility model provides a kind of magnetic compasses, can effectively solve the problem that above-mentioned prior art exists.

To achieve these goals, the technical solution adopted in the utility model is: a kind of magnetic compasses for teaching that is applied to the metal material blackboard, comprise that one is used for fixing powerful annular magnet and the cylindrical structural that two metal rotation arms are housed, scale is arranged on the metal arm, below one end bush of chalk is installed, there is perforate at cylindrical structural both sides and two ends, internal thread and a supporting screw are arranged at this structure top, screwing screw can fix metal arm, the cylindrical structural lower end has with plastics bush of chalk the same below the metal arm end, entangle with rubber band the outside, be used for to insert and fixing chalk, and this cylindrical structural inserts in the circular hole of annular magnet.Utilize magnet cylindrical structural and metal arm tightly can be held the sucking action of metal and can slippage out, so magnet not only holds blackboard but also held turning arm, played connection function, cylindrical structural above rotating can be realized one-handed performance and the circle that draws required size at blackboard easily comes, moreover, can also regulate as required the length of two ends turning arm, easily realization once draws two concentric circles.

As preferably, described turning arm is made with metal.

As preferably, described turning arm can be fixed by top screw.

As preferably, can draw concentric circles during being uneven in length of described turning arm both sides.

As preferably, described magnet has attracted turning arm, and the blackboard surface is fixed in absorption again.

As preferably, described cylindrical structural inserts in the circular hole of annular magnet.

Compared with prior art, the beneficial effect of this utility model: simple in structure, cost is low, is suitable for using at the blackboard of all kinds of metal materials, and has realized the circle of singlehanded picture known radius or drawn concentric circles.

Description of drawings

Fig. 1 is the utility model structural representation;

Fig. 2 is the utility model profilograph;

Fig. 3 is top view of the present utility model;

Fig. 4 is upward view of the present utility model.

The specific embodiment

The utility model is described in further detail below in conjunction with drawings and the specific embodiments.

Referring to Fig. 1-4, a kind of magnetic compasses for teaching (Fig. 1), comprise 5, two metal rotation arms 1 of annular magnet and 3, there is the

sleeve

4 and 7 of dress chalk at the turning arm two ends, in the jack in the middle of turning arm 1 and the 3 juxtapositions insertion cylindrical structural 8, the screw 2 of turn upper end can be fixed

turning arm

1 and 3, and bush of chalk 6 is arranged at the cylindrical structural bottom, bush of chalk 4, rubber band 10 is respectively being overlapped in 7 outsides, then with in the circular hole 9 in the middle of the bush of chalk 6 insertion annular magnets 5 of cylindrical structural.

During use, give first bush of

chalk

4,6, load onto isometric chalk for 7 li,

sleeve

4,7 external application rubber bands, 10 bandings, chalk end exceed two millimeters in sleeve and get final product, with two turning

arms

1,3 adjust to suitable length (two turning arm length are unequal when drawing two concentric circles), fix with screw 2, annular magnet is put on the blackboard will draws round position, then cylindrical structural 8 is inserted in the circular hole 9 of environment magnet, make three sleeves 4, the chalk end of 6,7 lower ends can both touch blackboard, rotates following cylindrical structural 8 or clockwise rotates screw 2 and namely can easily finish the work of picture circle on the blackboard.Magnet can be moved on to blackboard together with turning arm etc. after painting places Anywhere and needn't take off again and be put on the lectern.

Claims

1. the utility model discloses a kind of magnetic compasses for teaching that is applied to the metal material blackboard, comprise that one is used for fixing powerful annular magnet and the cylindrical structural that two metal rotation arms are housed, scale is arranged on the metal arm, below one end bush of chalk is installed, there is perforate at cylindrical structural both sides and two ends, internal thread and a supporting screw are arranged at this structure top, screwing screw can fix metal arm, the cylindrical structural lower end has with plastics bush of chalk the same below the metal arm end, entangle with rubber band the outside, be used for to insert and fixing chalk, this cylindrical structural inserts in the circular hole of annular magnet.

2. a kind of magnetic compasses for teaching according to claim 1, it is characterized in that: described turning arm is made with metal.

3. a kind of magnetic compasses for teaching according to claim 1, it is characterized in that: described turning arm can be fixed by top screw.

4. a kind of magnetic compasses for teaching according to claim 1, it is characterized in that: described magnet has attracted turning arm, and the blackboard surface is fixed in absorption again.

5. a kind of magnetic compasses for teaching according to claim 1 is characterized in that: in the circular hole of described cylindrical structural insertion annular magnet.