CN2292682Y

CN2292682Y - Definition compasses

Info

Publication number: CN2292682Y
Application number: CN 97205959
Authority: CN
Inventors: 马培业; 马鑫; 马奔
Original assignee: 马培业
Priority date: 1997-01-23
Filing date: 1997-01-23
Publication date: 1998-09-30
Anticipated expiration: 2007-01-23

Abstract

The utility model discloses a definition compasses, comprising a centering point, an opening for holding a pen, a main rule, an auxiliary ruler and a locking device. The centering point is fixed at one end of the main rule, and the auxiliary rule is inserted in the main ruler from the other end; the opening for holding the pen is at the tail end of the auxiliary ruler, and the dimension and the scale line are respectively marked with the center of the centering point as a starting point on the main ruler and the center of the opening for holding the pen as the starting point; the locking device is arranged between the main ruler and the auxiliary ruler. The distance between the fixed point and the movable point of the definition compasses can be directly displayed; the definition compasses have the advantages of convenient operation and are convenient for students to understand the definition of the circle in the teaching process.

Description

Definition compasses

The utility model relates to a kind of compasses, especially a kind of Definition compasses that helps to understand round notion.

Textbook is for the definition of circle: " equaling the set (track) of the point of fixed length to the fixed point distance ".With old-fashioned compasses this notion of imparting knowledge to students, distance fixed because of can not directly showing, moving 2, then needing of desiring to know measured by means of ruler, not only makes troubles to the operator, and key is to bring some interference and difficulty to the notion of the correct complete understanding circle of student.

The purpose of this utility model is to overcome the defective that prior art exists, and a kind of Definition compasses of circle is provided, and the distance of its fixed, moving point-to-point transmission can directly be shown.

The purpose of this utility model realizes as follows: these compasses still have centering point and pen clip mouth, it also has main scale and secondary chi, the centering point is fixed on an end of main scale, secondary chi is inserted in the main scale from the other end, the pen clip mouth is at the tail end of secondary chi, be to be that starting point is marked with the size scale line along its length with pen clip mouth center on starting point, the secondary chi with the sharp center of feeling relieved on the main scale, between main scale and the secondary chi locking device arranged.

Locking device is made of lock-screw and locking nut, and the straight trough that the screw mandrel of lock-screw was partly gone here and there on the secondary chi is inserted in the circular hole of main scale, and its upper end screws in locking nut, and the tail end boss is stuck on the secondary chi.

Locking device also can directly be provided with lock-screw on main scale, screw this screw and directly withstand on the secondary chi and compress.

The fixed length that this Definition compasses can obtain differing in size by push-and-pull major-minor chi, thereby the circle of the different sizes of drawing, these compasses are easy to operate, show that fixed length is directly perceived, help the notion of the correct complete understanding circle of student.

Below in conjunction with accompanying drawing the utility model is further described.

Fig. 1 is the front view of the utility model Definition compasses.

Fig. 2 is the vertical view of the utility model Definition compasses.

With reference to Fig. 1, Fig. 2, these compasses are made of main scale 3, secondary chi 6, centering point 1 and the locking device that is made of lock-screw 5 and locking nut 4.Centering point 1 usefulness locknut 2 is fixed on the left end of main scale 3, is that starting point indicates the size scale line to the right with sharp 1 central point of feeling relieved on the main scale 3.Secondary chi 6 is inserted in the groove of main scale 3 from the right-hand member of main scale 3, and the effect of groove is the swing of the secondary chi 6 of restriction.The right-hand member of secondary chi 6 has pen clip mouth 7, is used for things such as clamping pencil, chalk, and the central point with pen clip mouth 7 on the secondary chi 6 indicates the size scale line left.Locking device is used for after determining fixed length main scale 3 and 6 lockings of secondary chi, the straight trough that the screw mandrel of lock-screw 5 was partly gone here and there on the secondary chi 6 is inserted in the circular hole of main scale 3, the screw mandrel upper end screws in locking nut 4, the tail end boss blocks secondary chi 6, screw locking nut 4, main scale 3 and secondary chi 6 can be compressed and abut in together, play locking action.

Claims

1, a kind of Definition compasses, relate to centering point and pen clip mouth, it is characterized in that: these compasses also have main scale (3) and secondary chi (6), centering point (1) is fixed on an end of main scale (3), secondary chi (6) is inserted in the main scale (3) from the other end, pen clip mouth (7) is at the tail end of secondary chi (6), and it is that starting point, secondary chi (6) are that starting point is marked with the size scale line along its length with pen clip mouth (7) center upward that main scale (3) is gone up with the point of feeling relieved (1) center, between main scale (3) and the secondary chi (6) locking device is arranged.

2, Definition compasses according to claim 1, it is characterized in that: locking device is made of lock-screw (5) and locking nut (4), the straight trough that the screw mandrel of lock-screw (5) was partly gone here and there on the secondary chi (6) is inserted in the circular hole of main scale (3), its upper end is rotary with locking nut (4), and the tail end boss is stuck on the secondary chi (6).