CN203876443U

CN203876443U - Blackboard writing compasses

Info

Publication number: CN203876443U
Application number: CN201420338402.8U
Authority: CN
Inventors: 王燕
Original assignee: Individual
Current assignee: Individual
Priority date: 2014-06-18
Filing date: 2014-06-18
Publication date: 2014-10-15
Anticipated expiration: 2024-06-18

Abstract

The utility model discloses a pair of blackboard writing compasses and belongs to the technical field of teaching appliances. The pair of blackboard writing compasses comprises a fixed compasses foot and a rotating compasses foot which are installed together through a hinged shaft. An arc-shaped connecting piece is fixedly installed on the fixed compasses foot and extends towards the rotating compasses foot and extends out of the rotating compasses foot. The arc-shaped connecting piece is provided with an arc-shaped through groove, the circle center of the arc-shaped through groove coincides with the center of the hinged shaft, the arc-shaped connecting piece is connected with the rotating compasses foot through a screw, the screw penetrates the arc-shaped through groove and is in threaded connection with the rotating compasses foot, the end of the fixed compasses foot is connected with a sucker through a ball head joint bearing, and a piece of chalk is installed at the end of the rotating compasses foot. The pair of blackboard writing compasses solves the technical problem that the position of the fixed compasses foot moves easily at present, the distance between a chalk point of the compasses and the end of the fixed compasses foot varies easily, so that a drawn circle is irregular; and the pair of blackboard writing compasses is widely applied to mathematical education.

Description

Writing on the blackboard compasses

Technical field

The utility model relates to teaching appliance technical field, relates in particular to a kind of writing on the blackboard compasses for mathematical education.

Background technology

In mathematical education, compasses are one of indispensable instruments, be often used in blackboard upper drawing circle or arc, these compasses all comprise swing handle, and swing handle is provided with fixedly regulation foot and a rotation regulation foot, wherein fixedly the end of regulation foot is provided with metal needle, and this metal pinprick is determined the center of circle on blackboard; Rotation regulation foot end is provided with chalk, and this chalk is for the periphery of picture circle or arc, conventionally needs to determine that rotation regulation foot and the fixing angle between regulation foot determine picture radius of circle, and rotates regulation foot and fixedly between regulation foot, can only pass through frictional force fixed position between the two.But when compasses were used after a period of time; rotation regulation foot and fixedly process break-in between regulation foot; just can become flexible; therefore the phenomenon that there will be rotation regulation foot automatically to open at picture bowlder; to such an extent as to draw circular irregular, and because the plate face of blackboard is harder, metal needle can not thrust blackboard; so can only be against the surface of blackboard, drawing bowlder often can be because metal needle moves and causes picture to be justified unsuccessfully at blackboard surface location.

Therefore, based on above-mentioned defect, in teaching instrument field, for novel writing on the blackboard compasses, still have research and improved demand, this is also study hotspot and emphasis in current teaching appliance field, the starting point that the utility model is accomplished especially and power place.

Utility model content

For many defects of above-mentioned existence, the inventor, through a large amount of further investigations, after having paid sufficient creative work, thereby has completed the utility model.

Particularly, technical problem to be solved in the utility model is: a kind of writing on the blackboard compasses are provided, to solve at present the fixedly position of regulation foot, easily move, and the distance of the chalk nib of compasses and fixed gauge foot portion easily changes, cause picture to justify irregular technical problem.

For solving the problems of the technologies described above, the technical solution of the utility model is, a kind of writing on the blackboard compasses are provided, described writing on the blackboard compasses comprise swing handle, described swing handle is provided with fixedly regulation foot and a rotation regulation foot, the end of described rotation regulation foot is installed on the end of described fixedly regulation foot by a jointed shaft, in described fixedly regulation foot, fixedly mount an arc connector, described arc connector extends and extends described rotation regulation foot to described rotation regulation foot, described arc connector is provided with an arc-shaped slot, the center of circle of described arc-shaped slot is consistent with the center of described jointed shaft, described arc connector links together by a screw and described rotation regulation foot, described screw is through described arc-shaped slot and the described rotation regulation foot that is threaded, the end of described fixedly regulation foot connects a sucker by bulb joint bearing, and the end of described rotation regulation foot is provided with chalk.

In writing on the blackboard compasses of the present utility model, as a kind of optimal technical scheme, a sleeve is installed in the end of described rotation regulation foot, described sleeve one end is provided with a hole that holds chalk, the other end is threaded with described rotation regulation foot, in described sleeve, be slidably fitted with the chalk sleeve of a clamping chalk end, between the end of described chalk sleeve and rotation regulation foot, be provided with the first Compress Spring, described chalk sleeve and have between the sleeve ends in described hole and be provided with the second Compress Spring, the elastic force of described the second Compress Spring is less than the elastic force of described the first Compress Spring, described the second Compress Spring is set on described chalk, described chalk passes described hole, the end of described sleeve is provided with one for limiting the universal wheel of chalk extension elongation.

Adopted technique scheme, the beneficial effects of the utility model are:

(1) owing to having designed arc connector, making to rotate regulation foot is fixed together by screw and arc connector, and arc connector is fixedly connected with fixing regulation foot, therefore, guaranteed rotation regulation foot and fixedly the folding angle between regulation foot can not change;

(2) because the end of fixing regulation foot is by bulb joint bearing connecting sucker, during use, sucker is adsorbed on to blackboard surface, has guaranteed that fixedly the end of regulation foot can not be moved, thereby guaranteed the toroidal rule that draws;

(3) owing to being provided with unsteady chalk sleeve in sleeve, chalk sleeve is clamping chalk and ejecting a hole under the first Compress Spring active force, under limit element effect, the length that chalk stretches out a hole is certain, and after chalk wearing and tearing, the first Compress Spring continues chalk to eject, the length that assurance chalk contacts with blackboard is constant, therefore in the situation that fixedly regulation foot and rotation regulation foot angular separation degree are certain, the radius of circle that these compasses draw remains unchanged, in the same size;

(4) because sleeve is threaded with rotation regulation foot, can adjust the pretightning force of the first Compress Spring, again owing to being provided with the second Compress Spring, offset a part of chalk and be subject to the active force of the first Compress Spring, avoided chalk held out against by the first Compress Spring and caused pretightning force excessive and the defect of fracture, the service life of having extended chalk occur.

Accompanying drawing explanation

Fig. 1 is the structural representation of the utility model embodiment.

Wherein, in Fig. 1, each number designation refers to respectively following concrete meaning, element or parts.

In figure: 1, fixing regulation foot; 2, rotation regulation foot; 3, swing handle; 4, jointed shaft; 5, arc connector; 6, arc-shaped slot; 7, screw; 8, bulb joint bearing; 9, sucker; 10, sleeve; 11, chalk sleeve; 12, the first Compress Spring; 13, the second Compress Spring; 14, installing plate; 15, universal wheel; 16, holding screw; 17, chalk.

The specific embodiment

Below in conjunction with accompanying drawing; by specific embodiment the utility model is elaborated; but the purposes of these property enumerated embodiments and object are only used for enumerating the utility model; not real protection scope of the present utility model is formed to any type of any restriction, more non-protection domain of the present utility model is confined to this.

As shown in Figure 1, writing on the blackboard compasses described in the utility model, comprise swing handle 3, swing handle 3 is provided with fixedly regulation foot 1 and a rotation regulation foot 2, the end of rotation regulation foot 2 is installed on the fixedly end of regulation foot 1 by a jointed shaft 4, fixedly in regulation foot 1, fixedly mount an arc connector 5, arc connector 5 extends and extends rotation regulation foot 2 to rotation regulation foot 2, arc connector 5 is provided with an arc-shaped slot 6, the center of circle of arc-shaped slot 6 is consistent with the center of jointed shaft 4, arc connector 5 links together by a screw 7 and rotation regulation foot 2, screw 7 is through arc-shaped slot 6 and the rotation regulation foot 2 that is threaded, during adjustment, first unclamp screw 7, adjustment rotation regulation foot 2 and fixedly the folding angle between regulation foot 1, then lock-screw 7, arc connector 5 and rotation regulation foot 2 are fixed together, folding angle is immobilized, fixedly the end of regulation foot 1 connects a sucker 9 by bulb joint bearing 8, the soft sucker that sucker 9 selects quality of rubber materials to make conventionally, and to guarantee that fixedly the end position of regulation foot 1 remains unchanged on the plate face of blackboard, the end of rotation regulation foot 2 is provided with chalk 17.

Inventor finds, in drawing circle process, when especially radius of a circle is larger, the wearing and tearing of chalk are more serious, can cause drawn circle head and the tail not overlap, therefore, inventor is through further investigation, develop following scheme: a sleeve 10 is installed in the end of rotation regulation foot 2, sleeve 10 one end are provided with a hole that holds chalk 17, the other end is threaded with rotation regulation foot 2, in sleeve 10, be slidably fitted with the chalk sleeve 11 of clamping chalk 17 ends, between the end of chalk sleeve 11 and rotation regulation foot 2, be provided with the first Compress Spring 12, chalk sleeve 11 and have between sleeve 10 ends in a hole and be provided with the second Compress Spring 13, the elastic force of the second Compress Spring 13 is less than the elastic force of the first Compress Spring 12, the second Compress Spring 13 is set on chalk 17, chalk 17 passes a hole, the end of sleeve 10 is provided with one for limiting the universal wheel 15 of chalk 17 extension elongations.For more convenient to use, the end of sleeve 10 is set with an installing plate 14, between installing plate 14 and sleeve 10, be provided with holding screw 16 for location, universal wheel 15 is arranged on installing plate 14, as for the position relationship of universal wheel 15 and chalk 17, can rotate as required installing plate 14 adjusts, make universal wheel 15 can either limit the length that chalk 17 stretches out, guarantee to offset with blackboard all the time, do not affect again mapping.

Although for for example and the object of description, and introduced structure and processing procedure shown in above-mentioned embodiment of the present utility model and accompanying drawing.But these are not detailed descriptions, scope of the present utility model can not be confined to this.For a person skilled in the art, can make numerous modifications and variations to above-mentioned embodiment of the present utility model, and these all modifications and/or variation are all included in as within claim limited range of the present utility model, do not depart from the scope and spirit of the present utility model that limit as claim.

Claims

1. writing on the blackboard compasses, comprise swing handle, described swing handle is provided with fixedly regulation foot and a rotation regulation foot, the end of described rotation regulation foot is installed on the end of described fixedly regulation foot by a jointed shaft, it is characterized in that, in described fixedly regulation foot, fixedly mount an arc connector, described arc connector extends and extends described rotation regulation foot to described rotation regulation foot, described arc connector is provided with an arc-shaped slot, the center of circle of described arc-shaped slot is consistent with the center of described jointed shaft, described arc connector links together by a screw and described rotation regulation foot, described screw is through described arc-shaped slot and the described rotation regulation foot that is threaded, the end of described fixedly regulation foot connects a sucker by bulb joint bearing, and the end of described rotation regulation foot is provided with chalk.

2. writing on the blackboard compasses as claimed in claim 1, it is characterized in that, a sleeve is installed in the end of described rotation regulation foot, described sleeve one end is provided with a hole that holds chalk, the other end is threaded with described rotation regulation foot, in described sleeve, be slidably fitted with the chalk sleeve of a clamping chalk end, between the end of described chalk sleeve and rotation regulation foot, be provided with the first Compress Spring, described chalk sleeve and have between the sleeve ends in described hole and be provided with the second Compress Spring, the elastic force of described the second Compress Spring is less than the elastic force of described the first Compress Spring, described the second Compress Spring is set on described chalk, described chalk passes described hole, the end of described sleeve is provided with one for limiting the universal wheel of chalk extension elongation.