CN203805576U

CN203805576U - Multi-proportion compasses

Info

Publication number: CN203805576U
Application number: CN201420194228.4U
Authority: CN
Inventors: 江有永; 施高萍; 王莺; 钟建国; 戴倩倩; 吴淑敏; 蒋梨荧; 潘婷
Original assignee: Zhejiang University of Water Resources and Electric Power
Current assignee: Zhejiang University of Water Resources and Electric Power
Priority date: 2014-04-22
Filing date: 2014-04-22
Publication date: 2014-09-03
Anticipated expiration: 2024-04-22

Abstract

The utility model relates to a pair of multi-proportion compasses through which the middle point of a straight line can be rapidly and accurately found out or a drawing with the corresponding proportion can be rapidly and accurately finished with the middle point as the circle center and the length of the straight line as the diameter without carrying out proportion multiplying or proportion dividing. According to the technical scheme, a plurality of constant-proportion holes are formed between a compasses needle of one compasses leg and a lead, the proportions of the distances between the constant-proportion holes and the two top ends of the compasses legs are 2:1, 2.5:1, 4:1 and 5:1 respectively, a pin sliding groove is formed between every two adjacent constant-proportion holes, the width of the pin sliding grooves is smaller than the diameter of the constant-proportion holes, a connection device penetrates through the corresponding constant-proportion holes of the two compasses legs to form hinge connection so that the two compasses legs can be connected, and during working, a half-ball plane side of a convex coupler is attached to the half-ball plane side of a concave coupler to form a ball shape. The multi-proportion compasses are suitable for drawing teaching and drawing in schools and are also suitable for workers of enterprises and public institutions to carry out drawing.

Description

How than compasses

Technical field

The utility model relates to a kind of compasses, particularly a kind of many than compasses.

Background technology

In the teaching process of drawing or drawing course, compasses are for carrying out the indispensable instrument of draw circles or circular arc, being usually used in construction with ruler and compasses.Yet in drawing course, often can run into the problem of existing one section of its mid point of straight line how to confirm, in known technology, way has two kinds: 1, first measure this line segment length, after remove 2 computings, then take and have line segment one end and measure acquisition mid point as benchmark; The method is wanted to measure size 2 times, the precision measuring will depend on the precision of measurer used, and in drafting instrument, the precision of the scale on conventional set square, ruler, T-square etc. is accurate to millimeter more, measure at every turn and all can produce one 1 millimeters of following errors, in addition, 2 computing also will be removed in centre, and in this way precision is not high in institute, and takes energy, time-consuming.2, need to do boost line, use compasses pin end to overlap line segment one end therewith, take that to be greater than half length of this line segment be radius, on these line segment both sides, respectively paint one section of circular arc, and then allow pin end overlap with the line segment other end, with same radius, on these line segment both sides, respectively paint one section of circular arc, this four arcs forms two intersection points, and the intersection point that connects these two intersection points and middle line segment i.e. the mid point of line segment for this reason, the method step is more, and step is more time-consuming, the more accumulated errors therebetween of step are just larger, during mapping, only need the mid point of this section of straight line, and these four sections of auxiliary circular arcs also need to wipe after finding mid point, comparatively bother, and time-consuming, sometimes also wipe unclean, make whole drawing more dirty and messy, in addition, while drawing the first two circular arc, owing to where not knowing with the intersection point of two circular arcs in back, if the circular arc of drawing is short, when drawing below two circular arcs, likely just can not form two intersection points, also to return to and repaint two circular arcs above, if the length that two circular arcs are drawn above, to increase the success rate crossing with two circular arc lines below, that is again for the work of wiping has below increased workload, visible the method is time-consuming, effort, precision is not high again, when usage ratio is drawn, need on the basis of dimensioning, be multiplied by ratio or divided by the computing of ratio, as the ratio of using 1:2.5 is when draw, will on the basis of former dimensioning, carry out the computing divided by 2.5, relatively waste time and energy, the operate approximately that sometimes also will round up, this has reduced again the precision of drawing.

In drawing course, often there will be these problems: how the one section of straight line 1, having existed, for will draw diameter of a circle, finds fast and accurately the center of circle in the situation that not measuring length.2, how known one section of straight line, find fast and accurately mid point in the situation that not measuring length.3,, when usage ratio is drawn, be not multiplied by ratio or just can complete fast and accurately the drawing of corresponding proportion divided by the computing of ratio.These are all the problems that drawing personnel and drawing educator will solve.

Summary of the invention

The technical problems to be solved in the utility model is: for the problem of above-mentioned existence, provide a kind of and can find fast and accurately the center of circle that the mid point of one section of straight line or this section of straight line of take are diameter, be not multiplied by ratio or just can complete fast and accurately divided by the computing of ratio the compasses that compare that corresponding proportion draws more.

The technical scheme that the utility model adopts is: how than compasses, to comprise two compass legs, every compass leg two ends arrange respectively compasses pin, pencil-lead, between the compasses pin of described compass leg and pencil-lead, arrange a plurality of surely than hole, fixed than pin slippage slot is set between hole, the well width of pin slippage slot is less than fixed than the diameter in hole, coupling arrangement penetrates two corresponding determining of compass leg and connects two compass legs than forming in hole to be hinged to fetch, and compasses pin and pencil-lead slope inwardly.

Described every compass leg arrange 4 fixed than hole, these 4 fixed is respectively 2:1,2.5:1,4:1,5:1 than hole to the distance ratio on compass leg two tops.

Described coupling arrangement is comprised of protruding coupling, spring banking stop, spring, recessed coupling, and it is spherical that described protruding coupling is set to semicircle, and the semi-round ball planar side centre position of protruding coupling arranges shallow slippage slot.

The width of described shallow slippage slot equals the width of compass leg, and the degree of depth of shallow slippage slot equals the thickness of compass leg.

Fixed than pin with protruding coupling semi-round ball central axes is set on described shallow slippage slot, surely than the diameter of pin, equals fixed than the diameter in hole, fixed than the length of pin equal two compass legs thickness and.

Described fixed than slippage pin is set on pin end face, the diameter of slippage pin equals the well width of pin slippage slot, the length of slippage pin be greater than two compass legs thickness and, the end of slippage pin arranges screw thread.

It is spherical that described recessed coupling is set to semicircle, and the semi-round ball planar side centre position of recessed coupling arranges dark slippage slot, and the width of dark slippage slot equals the width of compass leg, and the degree of depth of dark slippage slot equals 3 times of thickness of compass leg.

The Circularhole diameter of described spring banking stop equals the diameter of slippage pin, and the outside diameter of spring banking stop is greater than fixed than the diameter in hole and be less than the width of dark slippage slot.

Banking stop accommodation hole, spring accommodation hole, thread connection hole with recessed coupling semi-round ball central axes are inwardly set on described dark slippage slot successively, the diameter of banking stop accommodation hole is more than or equal to the outside diameter of spring banking stop, the degree of depth of banking stop accommodation hole equals the thickness of spring banking stop, the diameter of spring accommodation hole is more than or equal to the large footpath of spring, the degree of depth of spring accommodation hole equals the compression height of spring, and the hole surface in thread connection hole arranges screw thread and equates with the thread size of slippage pin end.

The two sides of described shallow slippage slot are concordant with the two sides of a compass leg wherein, the dark two sides of slippage slot and the two sides of another compass leg are concordant, fixed corresponding the determining than in hole of ratio that penetrates two compass legs that stack than pin, slippage pin penetrates in spring banking stop, spring more successively, slippage pin screws in thread connection hole and forms thread connection, and the semi-round ball planar side of protruding coupling and the laminating of the semi-round ball planar side of recessed coupling form a spheroidal.

The beneficial effects of the utility model are: 1, between the compasses pin of compass leg of the present utility model and pencil-lead, arrange a plurality of surely than hole, fixed than hole, to the distance ratio on compass leg two tops, be respectively 2:1, 2.5:1, 4:1, 5:1, fixed than pin slippage slot is set between hole, the well width of pin slippage slot is less than fixed than the diameter in hole, coupling arrangement penetrates two corresponding determining of compass leg and connects two compass legs than forming in hole to be hinged to fetch, so it is 1:1 that the utility model can carry out conventional ratio fast and accurately, 2:1, 2.5:1, 4:1, 5:1, 1:2, 1:2.5, 1:4, 9 kinds of ratios such as 1:5 are drawn, can find fast and accurately the center of circle that the mid point of one section of straight line or this section of straight line of take are diameter.2, it is spherical that protruding coupling of the present utility model and recessed coupling are semicircle, during work, the semi-round ball planar side of protruding coupling and the laminating of the semi-round ball planar side of recessed coupling form a spheroidal, hand is being pinched this ball, just there is the focusing surface of exerting oneself downward or upward, also can rotate this ball rotate the utility model draw out circle or circular arc, and no matter the angle of opening between the present invention's two legs is large or little, two compass leg intersections are a spheroidal all the time, shape can not change, hand is being pinched the utility model feel and can not changed, draw front and back are consistent, guarantee the result of use of the present embodiment.

Accompanying drawing explanation

Fig. 1 is that duty of the present utility model is the schematic perspective view of 1:2.5 or 2.5:1.

Fig. 2 is compass leg schematic perspective view of the present utility model.

Fig. 3 is coupling arrangement schematic perspective view of the present utility model.

Fig. 4 is three-dimensional explosive view of the present utility model.

Fig. 5 is protruding coupling schematic perspective view of the present utility model.

Fig. 6 is recessed coupling schematic perspective view of the present utility model.

Fig. 7 is installation of the present utility model or ratio transposing state schematic perspective view.

Fig. 8 is that duty of the present utility model is the schematic perspective view of 1:4 or 4:1.

The specific embodiment

As shown in Figures 1 to 4, the present embodiment comprises two compass legs 1, every compass leg 1 two ends arrange respectively compasses pin 2, pencil-lead 3, it is a plurality of fixed than hole 4 between the compasses pin 2 of compass leg 1 and pencil-lead 3, to arrange, when carrying out ratio drawing, to realize the ratio of determining fast and accurately of multiple ratio, carry out ratio drawing, fixed than pin slippage slot 12 is set between hole 4, the well width of pin slippage slot 12 is less than fixed than the diameter in hole 4, the radial position that guarantees 1 of coupling arrangement 5 and two compass leg is relatively stable, only, when needs change ratio, coupling arrangement 5 could carry out slippage to realize the switching of different proportion along pin slippage slot 12, coupling arrangement 5 penetrates the fixed of two compass leg 1 correspondences and connects two compass legs 1 than forming in hole 4 to be hinged to fetch, making two compass legs 1 be X-shaped intersects and can relatively rotate around intersection point place axis, the compasses of two routine techniques have so just been formed, and these two compasses positions are opposing, and interlock, wherein the compasses on one side rotate an angle, also can rotate an identical angle with those compasses of its opposing another side, if two pairs of opposing legs are long the same, so they paint circle or circular arc equate, the radius of circle or circular arc equates, two pairs of opposing legs are long different, so they paint circle or circular arc be unequal, the radius of circle or circular arc is unequal, if pair of leg is long, a pair of short legs, the long ratio of leg is 1:2, they paint circle or circular arc is just different large so, it is exactly that compasses of short-leg are painted and justified or 2 times of the radius of circular arc that those compasses of long leg are painted circle or the radius of circular arc, just can carry out the ratio of 1:2 or 2:1 draws, if the long ratio of leg is 1:5 or other ratio, just can carry out the ratio of 1:5 or other ratio draws, compasses pin 2 slopes inwardly with pencil-lead 3, when the opening angle of two compass legs 1 is zero degree, between compasses pin 2 and pencil-lead 3, be in the shape of the letter V, but work as the present embodiment in use, article two, between compass leg 1, there is opening angle, compasses pin 2 and pencil-lead 3 be vertical drawing or be similar to vertical drawing just, so more be conducive to improve the accuracy of drawing.

As shown in Figure 2, every compass leg of the present embodiment 1 arranges 4 to be determined than hole 4, these 4 fixed is respectively 2:1 than hole 4 to the distance ratio on 1 liang of top of compass leg, 2.5:1, 4:1, 5:1, when drawing, initial value ratio drawing is used at most, while needing, also can use other scale pattern, according to international standard ISO 5455-1979 and standard GB/T/T 14690-1993 regulation, magnification ratio should be selected 2:1, 5:1, 10:1 and more vast scale, reduce in scale should be selected 1:2, 1:5, 10:1 and smaller scale, also allow if desired other scale pattern of selection standard regulation, but in drawing teaching or work, carrying out the ratio that ratio drawing is conventional is 1:1, 2:1, 2.5:1, 4:1, 5:1, 1:2, 1:2.5, 1:4, 9 kinds of 1:5 etc., and the present embodiment can be realized the ratio drawing of above 9 kinds of ratios fast and accurately.

As shown in Figures 3 to 5, the present embodiment coupling arrangement 5 is comprised of protruding coupling 6, spring banking stop 7, spring 8, recessed coupling 9, guarantees the connection of two compass legs 1, determines a ratio accurately, and can switch different ratios; It is spherical that described protruding coupling 6 is set to semicircle, the semi-round ball planar side centre position of protruding coupling 6 arranges shallow slippage slot 10, the width of shallow slippage slot 10 equals the width of compass leg 1, the degree of depth of shallow slippage slot 10 equals the thickness of compass leg 1, during work, the compass leg 1 adjacent with shallow slippage slot 10 is just stuck in shallow slippage slot 10, compass leg 1 rotates shallow slippage slot 10 and also follows rotation, can guarantee that the semi-round ball planar side of protruding coupling 6 and the laminating of the semi-round ball planar side of recessed coupling 9 form a spheroidal.

Fixed than pin 11 with protruding coupling 6 semi-round ball central axes is set on shallow slippage slot 10, determine to equal fixed than the diameter in hole 4 than the diameter of pin 11, fixed than the length of pin 11 equal two compass legs 1 thickness and, during work, determine to penetrate the fixed than in hole 4 of two compass legs that stack 1 than pin 11, form the turning cylinder of two compass legs 1, and form a definite ratio.

Fixed than slippage pin 13 being set on pin 11 end faces, the diameter of slippage pin 13 equals the well width of pin slippage slot 12, and the diameter of slippage pin 13 is less than to be determined than the diameter in hole 4, can make slippage pin 13 in pin slippage slot 12, slide, according to the required change scale of drawing; The length of slippage pin 13 be greater than two compass legs 1 thickness and, when changing ratio, can promote the distance that recessed coupling 9 moves two compass leg 1 thickness, it is fixed more fixed than hole 4 than pin 11 disengagings to cause, and the diameter of slippage pin 13 is less than the fixed width that equals pin slippage slot 12 than the diameter in hole 4, slippage pin 13 just can slippage in pin slippage slot 12 like this, realizes the effect of change ratio; The end of slippage pin 13 arranges screw thread, the hole surface in thread connection hole 17 arranges screw thread and equates with the thread size of slippage pin 13 ends, slippage pin 13 screws in thread connection hole 17 and forms thread connection, and it is an organic whole that each parts of the present embodiment are connected.

As shown in Figure 6, it is spherical that the recessed coupling 9 of the present embodiment is set to semicircle, the semi-round ball planar side centre position of recessed coupling 9 arranges dark slippage slot 14, the width of dark slippage slot 14 equals the width of compass leg 1, the degree of depth of dark slippage slot 14 equals 3 times of thickness of compass leg 1, when work, the compass leg 1 adjacent with dark slippage slot 14 will be stuck in dark slippage slot 14, when changing ratio or in the installation process of beginning the present embodiment, promote recessed coupling 9 and to protruding coupling 6, move again the distance of two compass leg 1 thickness, it is fixed more fixed than hole 4 than pin 11 disengagings just to make, could change ratio or complete installation.

The Circularhole diameter of spring banking stop 7 equals the diameter of slippage pin 13, the outside diameter of spring banking stop 7 is greater than fixed than the diameter in hole 4 and be less than the width of dark slippage slot 14, spring banking stop 7 just can stop that spring 8 does not move axially to protruding coupling 6 one sides like this, make spring 8 have all the time one to act on protruding coupling 6 to the pulling force of recessed coupling 9 directions, it is fixed than in hole 4 to make to determine to remain on than pin 11, another effect is in change ratio, while carrying out slippage coupling arrangement 5, being unlikely to spring 8 directly rubs with compass leg 1, the spring wire head friction compass leg 1 that is unlikely to spring 8 makes spring 8 or compass leg 1 wearing and tearing.

Banking stop accommodation hole 15 with recessed coupling 9 semi-round ball central axes is inwardly set on dark slippage slot 14 successively, spring accommodation hole 16, thread connection hole 17, the diameter of banking stop accommodation hole 15 is more than or equal to the outside diameter of spring banking stop 7, the degree of depth of banking stop accommodation hole 15 equals the thickness of spring banking stop 7, the diameter of spring accommodation hole 16 is more than or equal to the large footpath of spring 8, the degree of depth of spring accommodation hole 16 equals the compression height of spring 8, when changing ratio or in the installation process of beginning the present embodiment, to move by indentation coupling 9 distance of two compass leg 1 thickness, if banking stop accommodation hole 15 is not set, spring accommodation hole 16, will make the groove depth of dark slippage slot 14 on the basis of 3 times of compass leg 1 thickness, increase again the thickness of a spring banking stop 7 and the compression height of spring 8, so just cause the groove of dark slippage slot 14 to attempt too large, thereby reduce the thickness at recessed coupling 9 ball tops, maybe can not meet mechanics requirement, also make in addition the breach that recessed coupling 9 these semi-round balls are cut increase, protruding coupling 6 is too large with the ball breach that recessed coupling 9 forms in use, affect result of use.

When the present embodiment is installed, first make corresponding the determining than hole 4 alignment of two compass legs 1, make thread connection hole 17, spring 8, spring banking stop 7, fixed than hole 4, each central axis of slippage pin 13 coincides, by indentation coupling 9, Compress Spring 8, two compass legs 1 are all stuck in dark slippage slot 14, rotating protruding coupling 6 screws in thread connection hole 17 slippage pin 13, until the semi-round ball planar side of protruding coupling 6 and the laminating of the semi-round ball planar side of recessed coupling 9 form a ball, the two sides of shallow slippage slot 10 are concordant with the two sides of a compass leg 1 wherein, the two sides of dark slippage slot 14 are concordant with the two sides of another compass leg 1, as shown in Figure 7, unclamp recessed coupling 9, effect due to spring 8, determine to remain on the fixed than in hole 4 of two compass legs that stack 1 than pin 11, slippage pin 13 remains on spring banking stop 7, in spring 8, completing the present embodiment installs.

If known one section of straight line, in the situation that not measuring length, with the present embodiment, find fast and accurately the embodiment of mid point to be: to make that the fixed 2:1's that remains on two compass legs 1 than pin 11 is fixed than in hole 4, if need to be from other ratio fixed more fixed than in hole 4 time than what be transferred to 2:1 hole 4, to move by indentation coupling 9 distance of two compass leg 1 thickness, Compress Spring 8, fixed more fixed than hole 4 than pin 11 disengagings, slippage pin 13 is in determining than hole 4, along determining than unclamping in hole 4 of pin slippage slot 12 slippage coupling arrangements 5 to 2:1, the pin summit of the present embodiment long leg one side and pencil-lead summit are placed on to the two ends of this section of straight line, the pin summit of short-leg one side and the distance between pencil-lead summit are half of this section of straight length, the pin summit of short-leg one side is overlapped one end of section straight line therewith, the pencil-lead summit of the short-leg one side therewith intersection point of section straight line is mid point, can this section of straight line be that diameter carries out draw circles or circular arc.

If the one section of straight line having existed will be for will draw diameter of a circle, in the situation that not measuring length, with the present embodiment, find fast and accurately the embodiment in the center of circle to be: to make that the fixed 2:1's that remains on two compass legs 1 than pin 11 is fixed than in hole 4, the pin summit of long leg one side and pencil-lead summit are placed on to the two ends of this section of straight line, the pin summit of short-leg one side and the distance between pencil-lead summit are the radius of this section of straight line, the pencil-lead summit of short-leg one side is overlapped one end of section straight line therewith, the position of this section of straight line in place, pin summit of short-leg one side is the center of circle, can this section of straight line be that diameter carries out draw circles or circular arc.

Use 1:2, 1:2.5, 1:4, when 1:5 ratio is drawn, do not remove in the situation of computing of ratio value, the embodiment that uses the present embodiment to complete fast and accurately corresponding proportion drawing is: make to determine to remain on the corresponding fixed than in hole 4 of two compass legs 1 than pin 11, according to drawings marked size, with two tops of long leg one side, measure length or radius, hand is pinched the ball of the semi-round ball planar side of protruding coupling 6 and the semi-round ball planar side of recessed coupling 9 laminating formation, use two tops of short-leg one side at the enterprising line length sign of drawing or draw circles or circular arc, can carry out as shown in Figure 1 1:2.5 ratio draws, can carry out as shown in Figure 7 1:5 ratio draws.

Use 2:1, 2.5:1, 4:1, when 5:1 ratio is drawn, do not take advantage of in the situation of computing of ratio value, the embodiment that uses the present embodiment to complete fast and accurately corresponding proportion drawing is: make to determine to remain on the corresponding fixed than in hole 4 of two compass legs 1 than pin 11, according to drawings marked size, with two tops of short-leg one side, measure length or radius, hand is pinched the ball of the semi-round ball planar side of protruding coupling 6 and the semi-round ball planar side of recessed coupling 9 laminating formation, use two tops of long leg one side at the enterprising line length sign of drawing or draw circles or circular arc, can carry out as shown in Figure 1 2.5:1 ratio draws, can carry out as shown in Figure 7 5:1 ratio draws.

While using 1:1 ratio to draw, can select short-leg one side or long leg one side can draw without adjusting ratio according to dimensioning size.

The utility model is suitable for drawing teaching and the drawing of school, is also suitable for the staff of the enterprises and institutions use of drawing.

Claims

1. one kind, compare compasses more, it comprises two compass legs (1), every compass leg (1) two ends arrange respectively compasses pin (2), pencil-lead (3), it is characterized in that: it is a plurality of fixed than hole (4) between the compasses pin (2) of described compass leg (1) and pencil-lead (3), to arrange, fixed than pin slippage slot (12) is set between hole (4), the well width of pin slippage slot (12) is less than fixed than the diameter of hole (4), coupling arrangement (5) penetrates corresponding the determining of two compass legs (1) and connects two compass legs (1) than forming in hole (4) to be hinged to fetch, compasses pin (2) slopes inwardly with pencil-lead (3).

2. according to claim 1 many than compasses, it is characterized in that: described every compass leg (1) arrange 4 fixed than hole (4), these 4 fixed is respectively 2:1,2.5:1,4:1,5:1 than hole (4) to the distance ratio on compass leg (1) two top.

3. according to claim 1 many than compasses, it is characterized in that: described coupling arrangement (5) is comprised of protruding coupling (6), spring banking stop (7), spring (8), recessed coupling (9), it is spherical that described protruding coupling (6) is set to semicircle, and the semi-round ball planar side centre position of protruding coupling (6) arranges shallow slippage slot (10).

4. according to claim 3 many than compasses, it is characterized in that: the width of described shallow slippage slot (10) equals the width of compass leg (1), the degree of depth of shallow slippage slot (10) equals the thickness of compass leg (1).

5. according to claim 4 many than compasses, it is characterized in that: the upper setting of described shallow slippage slot (10) is fixed than pin (11) with protruding coupling (6) semi-round ball central axes, fixed than the diameter of pin (11), equal fixed than the diameter of hole (4), fixed than the length of pin (11) equal two compass legs (1) thickness and.

6. according to claim 5 many than compasses, it is characterized in that: described fixed than on pin (11) end face, slippage pin (13) being set, the diameter of slippage pin (13) equals the well width of pin slippage slot (12), the length of slippage pin (13) be greater than two compass legs (1) thickness and, the end of slippage pin (13) arranges screw thread.

7. according to claim 3 many than compasses, it is characterized in that: it is spherical that described recessed coupling (9) is set to semicircle, the semi-round ball planar side centre position of recessed coupling (9) arranges dark slippage slot (14), the width of dark slippage slot (14) equals the width of compass leg (1), and the degree of depth of dark slippage slot (14) equals 3 times of thickness of compass leg (1).

8. according to claim 3 many than compasses, it is characterized in that: the Circularhole diameter of described spring banking stop (7) equals the diameter of slippage pin (13), the outside diameter of spring banking stop (7) is greater than fixed than the diameter of hole (4) and be less than the width of dark slippage slot (14).

9. according to claim 7 many than compasses, it is characterized in that: the banking stop accommodation hole (15) with recessed coupling (9) semi-round ball central axes is inwardly set on described dark slippage slot (14) successively, spring accommodation hole (16), thread connection hole (17), the diameter of banking stop accommodation hole (15) is more than or equal to the outside diameter of spring banking stop (7), the degree of depth of banking stop accommodation hole (15) equals the thickness of spring banking stop (7), the diameter of spring accommodation hole (16) is more than or equal to the large footpath of spring (8), the degree of depth of spring accommodation hole (16) equals the compression height of spring (8), the hole surface in thread connection hole (17) arranges screw thread and equates with the thread size of slippage pin (13) end.

10. according to the compasses that compare described in claim 1 or 2 or 3 or 4 or 5 or 6 or 7 or 8 or 9 more, it is characterized in that: the two sides of described shallow slippage slot (10) are concordant with the two sides of a compass leg (1) wherein, the two sides of dark slippage slot (14) are concordant with the two sides of another compass leg (1), fixed corresponding the determining than in hole (4) of ratio that penetrates two compass legs that stack (1) than pin (11), slippage pin (13) penetrates spring banking stop (7) more successively, in spring (8), slippage pin (13) screws in thread connection hole (17) and forms thread connection, the semi-round ball planar side laminating of the semi-round ball planar side of protruding coupling (6) and recessed coupling (9) forms a spheroidal.