CN201941426U

CN201941426U - Compasses for teaching

Info

Publication number: CN201941426U
Application number: CN2011200106652U
Authority: CN
Inventors: 张传林; 马楠
Original assignee: Individual
Current assignee: Individual
Priority date: 2011-01-06
Filing date: 2011-01-06
Publication date: 2011-08-24
Anticipated expiration: 2021-01-06

Abstract

The utility model discloses a pair of compasses for teaching, belonging to the mathematical teaching field and comprising a radius arm and a power press pole, wherein the radius arm is T-shaped, scale marks are carved on a T-shaped long arm body, and the tail end of the T-shaped long arm is provided with a chalk inserting hole; for the T-shaped short arm, one end is a circle centre locating point, the other end is a power bearing end which is sheathed outside the power press pole; the bottom end of the power bearing end is provided with a ratchet clamping component; the power press pole is provided with a drive component; the drive component is connected with the clamping component in a bearing way; and the bottom edge of the drive component is provided with a ratchet braking component. Compared with the prior art, the compass arm can be driven to describe the circle through the down pressure, therefore, the compasses are time-saving and labor-saving; as the T-shaped long arm body is caved with the scale marks, the radius can be measured without a straight scale; and a centering cone and a sucker which is arranged with the centering cone coaxially ensure the excursion of the circle centre not to happen when the circle is being described.

Description

Compasses for teaching

[technical field]

The utility model relates to a kind of mathematics teaching aid, particularly a kind of compasses for teaching that is applicable in the mathematical education at the blackboard upper drawing circle.

[background technology]

Often can use compasses in the mathematical education, at present general compasses structure mostly is the student with the simple amplification on the compasses size, and its structure is two disposable compasses arms of angle, and arm is terminal to be the rule point, and another arm end has the chalk jack.Above-mentioned compasses have the following disadvantages: 1. owing to the drawn circle of writing on the blackboard demonstration is bigger, compasses use painstaking; 2. use these compasses, radius just can be operated after need measuring with ruler, and is very inconvenient; When 3. drawing the garden on the frosted glass blackboard, the rule point easily skids, and can't feel relieved.

[utility model content]

Technical assignment of the present utility model is at above the deficiencies in the prior art, the compasses for teaching that provides a kind of light picture circle to demonstrate.

The technical scheme in the invention for solving the technical problem is: a kind of compasses for teaching is characterized in that: comprise that radius arm and power are by bar; Described radius arm is T-shaped, and long-armed arm is carved with graduation mark on one's body, and end has the chalk jack, and T shape galianconism one end is a center of circle fixed point, and the other end is the power socket end, is socketed in power by outside the bar; Described power socket end bottom is made as the fastener of ratchet, and power is provided with actuator by bar, between described actuator and the described fastener for accepting the brake component that described actuator and root edge are provided with ratchet.

Above-mentioned actuator is a screw rod; Accept the brake component of described actuator, edge is provided with screw thread within it, described actuator is pressed down by bar by described power or on when drawing, the thread by described screw rod is along the turn of screw thread, to drive the rotation of described brake component.

One chalk ejecting device is arranged in the above-mentioned chalk jack.

Above-mentioned center of circle fixed point comprises centering cone and coaxial mounted sucker.

Compared with prior art, the utlity model has following outstanding beneficial effect:

1, drive the compasses arm by downforce and carry out the picture circle, time saving and energy saving;

2, long-armed arm is carved with graduation mark on one's body, need not to measure radius with ruler again;

3, centering cone and coaxial mounted sucker guarantee that the picture bowlder center of circle can not produce skew.

[description of drawings]

Fig. 1 is a schematic appearance of the present utility model;

Fig. 2 is brake component of the present utility model and fastener three-dimensional exploded view.

[specific embodiment]

Below in conjunction with specification drawings and specific embodiments the utility model is further specified.

As shown in Figure 1, the utility model comprises that radius arm 1 and power are by bar 2; Described radius arm 1 is T-shaped, and long-armed 11 arms are carved with graduation mark (not drawing among the figure) on one's body, and end has chalk jack 12; T shape galianconism one end is a center of circle fixed point, and the other end is a power socket end 5, is socketed in power by outside the bar 2.Described center of circle fixed point comprises centering cone 6 and coaxial mounted sucker 7.

In the described chalk jack 12 a chalk ejecting device can also be arranged, not show among the figure.

Described power socket end 5 bottoms are made as the fastener 3 of ratchet 31, and power is a screw rod by being provided with actuator in the bar 2, have between described actuator and the described fastener 3 to accept the brake component 4 that described actuator and root edge are provided with ratchet 42.Accept the brake component 4 of described actuator, edge is provided with screw thread 41 within it.Make actuator drive the rotation of brake component 4 by described power by pressing down of bar 2, because described actuator is a screw rod, as shown in Figure 2, the described brake component 4 of accepting actuator, edge is provided with screw thread 41 within it, when actuator is pressed down, thread by screw rod is along the turn of screw thread 41, just changeing to drive described brake component 4, and be fastened in the ratchet 31 of fastener 3 by the set ratchet 42 of its root edge, fastener 3 is driven, and then drive described radius arm 1 long-armed 11 and be equidirectional rotation, finish the picture circle.

Need to prove; particular of the present utility model is described in detail the utility model; for a person skilled in the art, in the various conspicuous change of under the situation that does not deviate from spirit and scope of the present utility model it being carried out all within protection domain of the present utility model.

Claims

1. a compasses for teaching is characterized in that: comprise that radius arm and power are by bar; Described radius arm is T-shaped, and long-armed arm is carved with graduation mark on one's body, and end has the chalk jack, and T shape galianconism one end is a center of circle fixed point, and the other end is the power socket end, is socketed in power by outside the bar; Described power socket end bottom is made as the fastener of ratchet, and power is provided with actuator by bar, between described actuator and the described fastener for accepting the brake component that described actuator and root edge are provided with ratchet.

2. compasses for teaching according to claim 1 is characterized in that described actuator is a screw rod; Accept the brake component of described actuator, edge is provided with screw thread within it, described actuator is pressed down by bar by described power or on when drawing, the thread by described screw rod is along the turn of screw thread, to drive the rotation of described brake component.

3. compasses for teaching according to claim 1 is characterized in that a chalk ejecting device is arranged in the described chalk jack.

4. compasses for teaching according to claim 1 is characterized in that described center of circle fixed point comprises centering cone and coaxial mounted sucker.