CN101391550A - Drawing rule for drawing cycle - Google Patents

Abstract

The invention discloses a drawing ruler used for drawing roundness; the drawing ruler is characterized in that the drawing ruler comprises a fixed ruler which is fixedly marked by size calibration; the ruler body of the fixed ruler is provided with a dovetail groove which is inserted by a movable ruler with the swallow-tailed profile; a needle inserting hole is processed on the calibration starting point of the fixed ruler; a pen-inserting hole is processed respectively at two ends of the movable ruler; the size calibration of the fixed ruler is arranged from the left side to the right side by beginning with the needle-inserting hole; the size calibration of the movable ruler is arranged from the right side to the left side by beginning with the right pen-inserting hole; furthermore, the last calibration number of the fixed ruler is the same with the first calibration number of the movable ruler. The drawing ruler has the active effects that the drawing ruler is better than two-feet typed bow compass during the drawing process, and is not easy to move; furthermore, radium value can be read directly from the ruler, thus leading to objective teaching.

Description

Drawing rule for drawing cycle

Technical field

The application relates to educational aid.

Background technology

At present during primary school math teaching, the teacher carries out the demonstration of picture circle with traditional bifoot type compasses on blackboard, and this mode has the following disadvantages: it is movable easily 1, to use bipod, makes picture round inaccurate; 2, because the size that can't directly read radius makes the student be difficult for being familiar with intuitively radius.

Summary of the invention

The application's purpose is to paint circle operation inconvenience and problem intuitively not for solving the bifoot type compasses, and a kind of drawing rule for drawing cycle is provided.

For achieving the above object, the application's structure is, comprise a fixing fixed ruler that indicates size scale, on the blade of fixed ruler dovetail groove is arranged, inserting a section in the dovetail groove is swallow-tailed adjustable rule, scale starting point at fixed ruler is processed with pin holes, is processed with pen plughole respectively at the two ends of adjustable rule; The size scale number of fixed ruler begins to arrange from left to right from pin holes, and the size scale number of adjustable rule is from the arrangement that begins to turn left from the right side of right pen plughole, and last scale numeral of fixed ruler is identical with first scale numeral of adjustable rule.

During use, it is the center of circle that spicule is embedded into the fixed ruler pin holes, and chalk inserts in the pen plughole, can the picture circle on blackboard, and when radius of circle during smaller or equal to the number of division of fixed ruler, penholder is at adjustable rule terminal point pen plughole, reading from the fixed ruler.When radius of circle during greater than fixed ruler, penholder is at the starting point pen plughole of adjustable rule, and the number of division of reading adjustable rule at the terminal scale of fixed ruler place is and changes radius of circle.

The application's good effect is: these bifoot type compasses are handy when 1, drawing, and are not easy the changing of the relative positions.2, directly read the radius number from ruler, teaching is directly perceived.

Description of drawings

Fig. 1 is the schematic diagram of the embodiment of the present application.

Among the figure: 1---pin holes, 2---adjustable rule scale terminal point pen plughole, 3---fixed ruler, 4---adjustable rule, 5---adjustable rule scale starting point pen plughole.

The specific embodiment

As shown in Figure 1, the application comprises fixed ruler 3 and adjustable rule 4, adjustable rule 4 is inserted in the dovetail groove of fixed ruler 3 (dovetail groove does not draw among the figure), is processed with pin holes 1 in the scale starting point of fixed ruler 3, is processed with pen plughole 5 and 2 respectively at the scale starting point and the terminal point of adjustable rule 4; The size scale number of fixed ruler 3 is arranged from left to right from pin holes 1 beginning, i.e. 0-18cm; The size scale number of adjustable rule 4 is from right pen plughole 5 beginnings arrangements of turning left from the right side, i.e. 18-32cm, and as can be seen from the figure, last scale of fixed ruler 3 is digital identical with first scale numeral of adjustable rule, is 18cm.

During use, spicule is embedded into fixed ruler pin holes 1 is the center of circle, chalk inserts in the pen plughole, can draw on blackboard, and when radius of circle during smaller or equal to the number of division of fixed ruler 3, penholder is at adjustable rule terminal point pen plughole 2, reading from the fixed ruler 3.When radius of circle during greater than fixed ruler 3, penholder is at the starting point pen plughole 5 of adjustable rule 4, and the number of division of reading adjustable rule 4 at fixed ruler 3 terminal scale places (being the 18cm place) is this radius of circle.

Claims (1)

1, a kind of drawing rule for drawing cycle, it is characterized in that, it comprises a fixing fixed ruler that indicates size scale, on the blade of fixed ruler dovetail groove is arranged, inserting a section in the dovetail groove is swallow-tailed adjustable rule, scale starting point at fixed ruler is processed with pin holes, is processed with pen plughole respectively at the two ends of adjustable rule; The size scale number of fixed ruler begins to arrange from left to right from pin holes, and the size scale number of adjustable rule is from the arrangement that begins to turn left from the right side of right pen plughole, and last scale numeral of fixed ruler is identical with first scale numeral of adjustable rule.