CN202582439U - Non-full-circle pi ruler for measuring major outside diameter - Google Patents

Abstract

The utility model discloses a non-full-circle pi ruler for measuring a major outside diameter. The non-full-circle pi ruler comprises at least one ruler tape and at least one positioning tensioning and closed size measuring device, wherein the ruler tape comprises a rectangular-section flexible tape and two ruler heads; the positioning tensioning and closed size measuring device comprises an upper positioning mechanism with an upper positioning cylinder and an upper claw, a lower positioning mechanism with a lower positioning cylinder and a lower claw, as well as a tensioning and closed size measuring mechanism. When more than two ruler tapes are arranged, all the ruler tapes are connected in series by adopting tape hooks; similar to a traditional pi ruler, the non-full-circle pi ruler is characterized in that during measurement, the excircle to be measured is surrounded for a circle by one or more ruler tapes connected in series by the tape hooks and the positioning tensioning and closed size measuring device, and the diameter of the measured excircle is obtained according to the geometric and mechanical relationship. Two positioning cylinders are introduced on the traditional ruler tape and field connection measurement can be realized by adopting a plurality of ruler tapes, and thus the outside diameter measurement range corresponding to the single ruler tape can be greatly widened; and meanwhile, the total amount of the required ruler tapes is greatly reduced.

Description

A kind of non-full circle Π chi that is used for big outside diameter measuring

Technical field

The utility model relates to the measuring appliance of measuring big external diameter; Especially a kind of non-full circle

chi that is used for big outside diameter measuring belongs to the length metering field.

Background technology

The high precision of big external diameter and easy measurement are the problems in a long-term puzzlement length metering field, are difficult to solve well.Through measure girth then divided by π so that draw tested external diameter,

chi of having a scale is a big outside diameter measuring utensil that has been widely used; This utensil is light, operation is simple and easy; It is measured resulting girth and not only depends on the scale on

chi, also will consider the distortion of

chi after institute's pulling force that bears and the counter-force that rubs.Yet the precision of chi is not very high.A kind of improving one's methods with a kind ofly being called as the chi band, not having scale on it but two ends are connected with the belt of right angle angle bar is not intactly around a week; But stay next gap, through this gap of accurate measurement this pairing arc length in intersegmental crack of reduction and then draw tested external diameter.Equally, measure resulting girth and yet will consider the distortion of chi band after institute's pulling force that bears and the counter-force that rubs.Though this method is proved to be and has improved precision and effect is remarkable; Yet but have the another one problem: the chi band of a length-specific the gap of measuring that can be actually utilized be not very big, thereby the big outside diameter measuring scope of corresponding this single chi band is very limited.This is because measured surface is a circular arc, and therefore, in fact the angle bar plane, two right angles that constitutes the gap of surveying is not parallel; The gap is big more, and this uneven degree is big more, and the gap that will survey is a minimum value wherein; Like this, strengthen some gaps a little, measuring accuracy just is difficult to guarantee.Because the measurement range of single chi band is very limited, so, just need large numbers of chi bands when adopting this method to measure a certain in a big way tested big external diameter.

Summary of the invention

For addressing the above problem; The utility model discloses a kind of a kind of non-full circle

chi that is used for big outside diameter measuring after prior art is improved, adopt following technical scheme:

A kind of non-full circle

chi that is used for big outside diameter measuring; It is characterized in that this non-full circle

chi comprises one ruler band (1), a location tension at least and seals dimension measuring device (2);

The flexible strap (11) that it is rectangle that said chi band (1) comprises a cross section and two chi heads (12) that are connected to belt (11) two ends; The outside surface (121) of two chi heads (12) is cylindrical; After belt (11) is stretching; Belt (11) is corresponding to the center line of its square-section line of centres and outside surface (121) intersect vertical axis of two chi heads (12), and belt (11) is corresponding to the surface on long limit, its square-section and outside surface (121) parallel axes of two chi heads (12).The size of long limit, belt (11) square-section and minor face is called the width and the thickness of belt (11) respectively, and after belt (11) was stretching, the distance of shaft centers between the outside surface (121) of two chi heads (12) was called the length of chi band (1).

The tension of said location comprises one with sealing dimension measuring device (2) and goes up detent mechanism (21), a following detent mechanism (22) and at least one tension and sealing dimensional measurement mechanism (23); Last detent mechanism (21) comprises one and goes up positioning cylinder (212), one and have the going up of rise to the bait (211) of the last hook (2111) that can hook said chi head (12), an axle shape spool (213) and at least two and be the head bearing of rolling bearing (214); Outmost surface (2121) as the last positioning cylinder (212) of last positioning cylinder (212) outmost surface is cylindrical; Outside surface (121) parallel axes of its axis and the chi head (12) that is hooked by last hook (2111); Last positioning cylinder (212) inner packet contain two with coaxial, the poroid last positioning cylinder endoporus (2122) of the outmost surface (2121) of last positioning cylinder (212); At the last positioning cylinder window (2123) that has a window-like on these two between the positioning cylinder endoporus (2122); Head bearing (214) is installed in two respectively and goes up in the positioning cylinder endoporus (2122); Last axle (213) is installed in head bearing (214) endoporus, and rise to the bait (211) then are connected with last axle (213) and make last hook (2111) on it be exposed to positioning cylinder (212) outside and can be around the limited rotation of last positioning cylinder endoporus (2122) axis through last positioning cylinder window (2123); Said down detent mechanism (22) comprises lower shaft (223) and at least two that a following positioning cylinder (222), have the following hook (221) of the following hook (2211) that can hook said chi head (12), an axle shape and is the lower bearing of rolling bearing (224); Outmost surface (2221) as the following positioning cylinder (222) that descends positioning cylinder (222) outmost surface is cylindrical; Outside surface (121) parallel axes of the chi head (12) that hook (2211) hooks under its axis and the quilt; Following positioning cylinder (222) inner packet contain two with coaxial, the poroid following positioning cylinder endoporus (2222) of the outmost surface (2221) of following positioning cylinder (222); Between these two following positioning cylinder endoporus (2222), have the following positioning cylinder window (2223) of a window-like; Lower bearing (224) is installed in respectively in two following positioning cylinder endoporus (2222); Lower shaft (223) is installed in lower bearing (224) endoporus, and following hook (221) then is connected with lower shaft (223) and to make following hook (2211) on it be exposed to down positioning cylinder (222) through following positioning cylinder window (2223) outside and can be around descending the limited rotation of positioning cylinder endoporus (2222) axis; Said tension comprises an extension spring (231), a pulling force and sealing dimensional measurement mechanism (232), a last draw ring (235) that is connected with last detent mechanism (21) and a following draw ring (236) that is connected with following detent mechanism (22) of confirming this extension spring (231) pulling force that bears with sealing dimensional measurement mechanism (23); The said mutual relationship that goes up between detent mechanism (21), following detent mechanism (22) and tension and the sealing dimensional measurement mechanism (23) is: tension and sealing dimensional measurement mechanism (23) are positioned between detent mechanism (21) and the following detent mechanism (22) and also through last draw ring (235) on it and following draw ring (236) they are linked together respectively, are parallel to each other between outmost surface (2221) axis of outmost surface (2121) axis of last positioning cylinder (212) and following positioning cylinder (222).

The connected mode of said belt (11) and chi head (12) is: at first; On chi head (12), have the flat hole (122) of a outside surface (121) axis perpendicular to chi head (12); The xsect in this flat hole (122) has two parallel long limits; These two long limits are symmetrical in outside surface (121) axis of chi head (12); And its distance in addition, is processed with the counterbore (124) of some screw holes (123) and correspondence greater than the thickness of belt (11) perpendicular to outside surface (121) axis of this flat hole (122) and chi head (12); Secondly, each end in belt (11) two ends, corresponding with screw hole (123) is processed with some unthreaded holes (111); At last, two ends are inserted belt (11) and these two in the flat holes of two chi heads (12) (122) respectively and are inserted chi heads (12) in the flat hole (122) are screwed in screw hole (123) respectively through unthreaded hole (111) screw (13) respectively by belt (11) and be fixed together.

Said rising to the bait (211) is exposed to the outside end of positioning cylinder (212) for having the last hook (2111) on the last hook surface (21111) that is shaped as V-arrangement on it; The said hook (2111) of going up hooks chi head (12), and the outside surface (121) that means chi head (12) is tangent with last hook surface (21111); For belt (11) when last hook (2111) hooks chi head (12) with rise to the bait and do not interfere between (211), on rise to the bait (211), be positioned at the pawl surface (21111) of rising to the bait and locate to have a ringent opening of rising to the bait (2112).

Said hook (221) down is exposed to down the outside end of positioning cylinder (222) for having the following hook (2211) on the following hook surface (22111) that is shaped as V-arrangement on it; Said hook (2211) down hooks chi head (12), and the outside surface (121) that means chi head (12) is tangent with following hook surface (22111); In order when hook (2211) hooks chi head (12) down, not interfere between belt (11) and the following hook (221), a ringent hook opening (2212) is down located to have in hook surface (22111) under being positioned on the following hook (221).

Said tension comprises extension spring (231), outer tube (233), interior pipe (234), last draw ring (235), following draw ring (236), outer tube joint (237) and inner pipe joint (238) with sealing dimensional measurement mechanism (23); Wherein, Outer tube (233) and interior pipe (234) are all a pipe that contains coaxial inner and cylindrical; Last draw ring (235) and following draw ring (236) are all an annulus that contains coaxial inner and cylindrical; And last draw ring (235) cylindrical is littler than outmost surface (2121) diameter of last positioning cylinder (212), and (236 cylindricals are littler than outmost surface (2221) diameter of following positioning cylinder (222) for following draw ring.Tension with the annexation of sealing dimensional measurement mechanism (23) various piece is: outer tube (233) cylindrical and interior pipe (234) the endoporus clearance fit for can axially sliding relatively; Last draw ring (235) is connected with outer tube joint (237); Outer tube joint (237) is connected with outer tube (233), and outer tube joint (237) is connected with an end of extension spring (231), and the other end of extension spring (231) is connected with inner pipe joint (238); Interior pipe (234) is connected with inner pipe joint (238), and inner pipe joint (238) is connected with following draw ring (236).

Have on the said outer tube (233) window-like outer window of tube (2331) and with vernier groove its next-door neighbour, that be plane surface (2332); (2332) upper edge outer tube (233) endoporus axially engraves vernier groove (2333) on vernier groove surface; Pipe (234) cylindrical axially engraves main scale groove (2341) in the upper edge, position that interior pipe (234) cylindrical can come out through outer window of tube (2331), and vernier groove (2333) and main scale groove (2341) comprise that it is the said pulling force and sealing dimensional measurement mechanism (232) of vernier mechanism that their outer tube (233) of carrying and interior pipe (234) are formed one jointly.

According to the needs of actual measurement, two and above chi band (1) can be set, at this moment, the buckle (3) that quantity is less than set chi band (1) quantity 1 need be set in addition set chi band (1) is connected in series.Said buckle (3) has two hook-shaped buckle pawls (31), can the adjacent chi head (12) of two adjacent chi bands (1) be hooked together, and outside surface (121) axis of these two chi heads (12) is parallel to each other, and then these two chi bands (1) are connected in series.Respectively have a buckle pawl surface (311) that is shaped as V-arrangement on said two buckle pawls (31), these two buckle pawl surfaces (311) are arranged face-to-face and are parallel to each other; Buckle pawl (31) hooks chi head (12), and the outside surface (121) of chi head (12) is tangent with the buckle pawl surface (311) on the buckle pawl (31); In order not interfere between belt (11) when buckle pawl (311) hooks chi head (12) and the buckle (31), on buckle (31), to be positioned at two buckle pawl surfaces (311) and to locate to have two ringent buckle openings (32); In addition; When the design of buckle pawl (311) and chi head (12) must guarantee when two that are linked together by buckle pawl (311) or above chi band (1) are measured, to surround tested cylindrical (0); Buckle pawl (311) can not contact with tested cylinder (0), thereby the outside surface (121) of each the chi head (12) that is hooked by buckle pawl (311) is contacted with tested cylindrical (0).

Advantage of the utility model and remarkable result: in essence, the chi band in the present invention and the background technology has similar measuring principle, thereby has close measuring accuracy.Different is; The present invention has taked two main measures to improve performance: the one, introduced two positioning cylinders; Make in background technology the gap between two right angle angle bar will measuring become in non-full circle

chi distance of shaft centers between two parallel cylinders; So; As long as the diameter of these two cylinders is selected enough greatly; Just can increase the distance of shaft centers between these two cylinders that to survey greatly, thereby increase the big outside diameter measuring scope of the pairing non-full circle of single chi band

chi greatly; The 2nd, adopt and can measure big external diameter, because the combined effect of the chi band 1 of different length can significantly reduce and measure the needed chi band sum of the tested external diameter of a certain scope more than on-the-spot connection of one chi band.In addition; The on-the-spot distance of shaft centers of accurately measuring between two parallel cylinders is also much easier than the gap between two right angle angle bar measuring non-equidistance, and the present invention adopts the mechanism of original measurement pulling force directly to draw this distance of shaft centers then further to have simplified this operation.At last; Different with tradition chi in the background technology or chi band is; The power that the chi band is born among the present invention needs not be constant force; The introducing of hook structure in addition, the operation of device is easier.

Description of drawings

Fig. 1 is the utility model embodiment front elevation when adopting tension of one ruler band (1) and one location and sealing dimension measuring device (2) to measure big external diameter, and wherein D is tested cylindrical (a 0) diameter;

Fig. 2 is the right view of Fig. 1;

Fig. 3 is the utility model embodiment front elevation when adopting the big external diameter of two chi bands (1), location tension and sealing dimension measuring device (2) and a buckle (3) measurement, and wherein D is tested cylindrical (a 0) diameter;

Fig. 4 is the right view of Fig. 3;

Fig. 5 is that the location tension is located partial enlarged view with sealing dimension measuring device (2) among Fig. 2 or Fig. 4;

Fig. 6 is the A-A cut-open view of Fig. 5;

Fig. 7 is the B-B cut-open view of Fig. 5;

Fig. 8 is the C-C cut-open view of Fig. 5;

Fig. 9 is the II place partial enlarged view of Fig. 6;

Figure 10 is the E-E cut-open view of Fig. 9;

Figure 11 is the F-F cut-open view of Fig. 9;

Figure 12 is the I place partial enlarged view of Fig. 5;

Figure 13 is the D-D cut-open view of Fig. 5;

Figure 14 is the III place partial enlarged view of Fig. 6;

Figure 15 is the G-G cut-open view of Figure 14;

Figure 16 is the H-H cut-open view of Figure 14;

Figure 17 is that detent mechanism on the embodiment of the invention (21) is located local shaft side figure;

Figure 18 is that detent mechanism under the embodiment of the invention (22) is located local shaft side figure;

Figure 19 is that buckle among Fig. 3 (3) is located local amplification view;

Figure 20 is the V place partial enlarged view of Figure 19 I;

Figure 21 is the J-J cut-open view of Figure 20;

Figure 22 is the K-K cut-open view of Figure 20;

Figure 23 is that the utility model embodiment adopts one ruler band (1) to measure the big external diameter principle schematic of tested cylindrical when being in prone position;

Figure 24 is that the utility model embodiment adopts two chi bands (1) to measure the big external diameter principle schematic of tested cylindrical when being in prone position.

Embodiment

Drawing reference numeral explanation: the tested cylindrical of 0-; 1-chi band; The 11-belt; The 111-unthreaded hole; 12-chi head; The outside surface of 121-chi head 12; The flat hole of 122-; The 123-screw hole; The 124-counterbore; The 13-screw; The 14-spring washer; Tension of 2-location and sealing dimension measuring device; The last detent mechanism of 21-; 211-rises to the bait; The last hook of 2111-; The last hook of 21111-surface; The 2112-opening of rising to the bait; The last positioning cylinder of 212-; The outmost surface of the last positioning cylinder 212 of 2121-; The last positioning cylinder endoporus of 2122-; The last positioning cylinder window of 2123-; The last positioning cylinder of 2124-extends cylinder; The last axle of 213-; The 214-head bearing; Detent mechanism under the 22-; Hook under the 221-; Hook under the 2211-; Hook surface under the 22111-; Hook opening under the 2212-; Positioning cylinder under the 222-; The outmost surface of positioning cylinder 222 under the 2221-; Positioning cylinder endoporus under the 2222-; Positioning cylinder window under the 2223-; Positioning cylinder extends cylinder under the 2224-; The 223-lower shaft; The 224-lower bearing; 23-tension and sealing dimensional measurement mechanism; The 231-extension spring; 232-pulling force and sealing dimensional measurement mechanism; The 233-outer tube; The outer window of tube of 2331-; 2332-vernier groove surface; 2333-vernier groove; Pipe in the 234-; 2341-main scale groove; The last draw ring of 235-; Draw ring under the 236-; The 237-outer tube joint; The 238-inner pipe joint; The 3-buckle; 31-buckle pawl; 311-buckle pawl surface; 32-buckle opening.

Like Fig. 1～shown in Figure 4, the embodiment of the invention comprises at least one ruler band 1, a location tension and sealing dimension measuring device 2.During measurement, different according to set chi band 1 quantity, need to adopt different configurations.Illustrated in figures 1 and 2 is configuration when a chi band 1 being set measuring, and it comprises a chi band 1 and a location tension and seals dimension measuring device 2; Fig. 3 and shown in Figure 4 be configuration when two chi bands 1 being set measuring, the buckle 3 that it comprises two chi bands 1, location tension and sealing dimension measuring device 2 and is provided with in addition, wherein buckle 3 is used for two chi bands 1 are connected in series; By that analogy, three chi bands 1 can be set also, two buckles 3 that the configuration during measurement comprises three chi bands 1, location tension and sealing dimension measuring device 2 and is provided with in addition, wherein two buckles 3 are used for three chi bands 1 are connected in series, or the like.Wherein, set buckle 3 quantity lack 1 than set chi band 1 quantity.

Like Fig. 9, Figure 10, Figure 14 and shown in Figure 15; The flexible steel belt 11 that it is rectangle that chi band 1 comprises a cross section and two steel chi heads 12 that are connected to belt 11 two ends; The outside surface 121 of two chi heads 12 is cylindrical; After belt 11 was stretching, corresponding to the center line of its square-section line of centres and outside surface 121 intersect vertical axis of two chi heads 12, and belt 11 was corresponding to the surface on long limit, its square-section and outside surface 121 parallel axes of two chi heads 12.

As shown in Figure 5, location tension and sealing dimension measuring device 2 comprise one and go up detent mechanism 21, following detent mechanism 22 and two tensions and sealing dimensional measurement mechanism 23; Like Fig. 6, Fig. 8, Fig. 9 and shown in Figure 17; Last detent mechanism 21 comprises steel that positioning cylinder on the steel 212, one have the last hook 2111 that can hook said chi head 12 and rises to the bait that 213 and four on axle is the head bearing 214 of rolling bearing on the steel of 211, axle shapes; The outmost surface 2121 of last positioning cylinder 212 is cylindrical; Outside surface 121 parallel axes of its axis and the chi head 12 that is hooked by last hook 2111; Last positioning cylinder 212 inner packet contain two outmost surface 2121 coaxial, poroid last positioning cylinder endoporus 2122 with last positioning cylinder 212; Have between the positioning cylinder endoporus 2122 on these two a window-like on positioning cylinder window 2123 (shown in figure 17); Head bearing 214 is installed in two respectively and goes up in the positioning cylinder endoporus 2122; Last axle 213 is installed in head bearing 214 endoporus, rises to the bait 211 then to be connected with last axle 213 and to make last hook 2111 on it be exposed to positioning cylinder 212 outsides and can be around the limited rotation of last positioning cylinder endoporus 2122 axis through last positioning cylinder window 2123; Shown in Fig. 6, Figure 13, Figure 14 and 18; Steel lower shaft 223 and four that said down detent mechanism 22 comprises hook under the steel that positioning cylinder under the steel 222, have the following hook 2211 that can hook said chi head 12 221, an axle shape are the lower bearing 224 of rolling bearing; The outmost surface 2221 of following positioning cylinder 222 is cylindrical; Outside surface 121 parallel axes of the chi head 12 that hook 2211 hooks under its axis and the quilt; Following positioning cylinder 222 inner packet contain two outmost surface 2221 coaxial, poroid following positioning cylinder endoporus 2222 with following positioning cylinder 222; Between these two following positioning cylinder endoporus 2222, have the following positioning cylinder window 2223 (shown in figure 18) of a window-like; Lower bearing 224 is installed in respectively in two following positioning cylinder endoporus 2222; Lower shaft 223 is installed in lower bearing 224 endoporus, and following hook 221 then is connected with lower shaft 223 and to make following hook 2211 on it be exposed to down positioning cylinder 222 through following positioning cylinder window 2223 outside and can be around descending the limited rotation of positioning cylinder endoporus 2222 axis; As shown in Figure 7, said tension and sealing dimensional measurement mechanism 23 comprise pulling force that an extension spring 231, one confirm that 231 of this extension springs bear pulling force and seal dimensional measurement mechanism 232, a last draw ring 235 that is connected with last detent mechanism 21 and a following draw ring 236 that is connected with following detent mechanism 22; Like Fig. 5, Fig. 6, Fig. 7, Fig. 8 and shown in Figure 13; Said detent mechanism 21, the mutual relationship between detent mechanism 22 and two tensions and the sealing dimensional measurement mechanism 23 down of going up: two tensions and sealing dimensional measurement mechanism 23 are also linking together them through draw ring 235 on it and following draw ring 236 respectively between last detent mechanism 21 and the following detent mechanism 22; Be parallel to each other between outmost surface 2121 axis of last positioning cylinder 212 and outmost surface 2221 axis of following positioning cylinder 222; Tension and the extension spring 231 of sealing in the dimensional measurement mechanism 23 can strained or loosen to the distance of shaft centers that this layout make to change goes up between the outmost surface 2221 of outmost surface 2121 and following positioning cylinder 222 of positioning cylinder 212; The pulling force that is born between detent mechanism 21 and the following detent mechanism 22 is changed; Simultaneously, also make pulling force and the distance of shaft centers (sealing size) that seals between outmost surface 2221 axis of outmost surface 2121 axis and following positioning cylinder 222 that dimensional measurement mechanism 232 can confirm last positioning cylinder 212 in tension and the sealing dimensional measurement mechanism 23.

Like Figure 19 and shown in Figure 20, buckle 3 is a steel, has two hook-shaped buckle pawls 31 on it, can the adjacent chi head 12 of two adjacent chi bands 1 be hooked together and outside surface 121 axis of these two chi heads 12 are parallel to each other.

Further specify the details of embodiment below.

Like Fig. 9, Figure 10, Figure 14 and shown in Figure 15; The connected mode of belt 11 and chi head 12 is: at first, on chi head 12, have a flat hole 122 perpendicular to outside surface 121 axis of chi head 12, the xsect in this flat hole 122 has two parallel long limits; These two long limits are symmetrical in outside surface 121 axis of chi head 12; And its distance in addition, is processed with the counterbore 124 of three screw holes 123 and correspondence greater than the thickness of belt 11 perpendicular to outside surface 121 axis of this flat hole 122 and chi head 12; Secondly, each end in belt 11 two ends, corresponding with screw hole 123 is processed with three unthreaded holes 111; At last, the belt 11 that inserts respectively in two chi heads, the 12 flat holes 122 of two ends is inserted chi head 12 in the flat hole 122 respectively by belt 11 and is equipped with three spring washers 14 by the screw 13 that screws in screw holes 123 through unthreaded hole 111 respectively and is fixed together with these two.

Like Fig. 9 and shown in Figure 11, rising to the bait 211 is exposed to the outside ends of positioning cylinder 212 for having the last hook 2111 of the last hook surperficial 21111 that is shaped as V-arrangement on it; Last hook 2111 hooks chi head 12, and the outside surface 121 that means chi head 12 is tangent with last hook surface 21111; For belt 11 when last hook 2111 hooks chi head 12 with rise to the bait and do not interfere between 211, be positioned at 21111 places, pawl surface of rising to the bait on 211 and have a ringent opening 2112 of rising to the bait rising to the bait.

Shown in Figure 14 and 16, it is the following hook 2211 that has the following hook surface 22111 that is shaped as V-arrangement on it that following hook 221 is exposed to down positioning cylinder 222 outside ends; Following hook 2211 hooks chi head 12, and the outside surface 121 that means chi head 12 is tangent with following hook surface 22111; In order when hook 2211 hooks chi head 12 down, not interfere between belt 11 and the following hook 221, on following hook 221, being positioned at down, 22111 places, hook surface have a ringent hook opening 2212 down.

As shown in Figure 8, last positioning cylinder 21 symmetria bilateralis are extended two outmost surface 2121 coaxial columned positioning cylinders of going up with last positioning cylinder 212 and are extended cylinder 2124;

Shown in figure 13, following positioning cylinder 21 symmetria bilateralis are extended two outmost surface 2221 coaxial columned positioning cylinders down with following positioning cylinder 222 and are extended cylinder 2224.

Like Fig. 7 and shown in Figure 12; Tension comprises extension spring 231, outer tube 233, interior pipe 234 with sealing dimensional measurement mechanism 23, goes up draw ring 235, draw ring 236, outer tube joint 237 and inner pipe joint 238 down; Wherein, Outer tube 233 is all a pipe that contains coaxial inner and cylindrical with interior pipe 234, and last draw ring 235 is all an annulus that contains coaxial inner and cylindrical with following draw ring 236, and; Last draw ring 235 outside diameters are littler than outmost surface 2121 diameters of last positioning cylinder 212, and following draw ring 236 outside diameters are littler than outmost surface 2221 diameters of following positioning cylinder 222.Tension with the annexation of sealing dimensional measurement mechanism 23 various pieces is: outer tube 233 cylindricals and the interior pipe 234 endoporus clearance fit for can axially sliding relatively; Last draw ring 235 is connected with outer tube joint 237; Outer tube joint 237 is connected with outer tube 233, and outer tube joint 237 is connected with an end of extension spring 231, and the other end of extension spring 231 is connected with inner pipe joint 238; In pipe 234 be connected with inner pipe joint 238, inner pipe joint 238 is connected with following draw ring 236.

Shown in figure 12; Have on the outer tube 233 window-like outer window of tube 2331 and with vernier groove its next-door neighbour, that be plane surface 2332; 2332 upper edge outer tubes, 233 endoporus axially engrave vernier groove 2333 on vernier groove surface; Pipe 234 cylindricals axially engrave main scale groove 2341 in the upper edge, position that interior pipe 234 cylindricals can come out through outer window of tube 2331; Vernier groove 2333 and main scale groove 2341 comprise outer tube 233 and interior pipe 234 common compositions said pulling force and sealing dimensional measurement mechanism 232 for vernier mechanism of carrying them, can measure outer tube 233 and interior pipe 234 axial distances of sliding relatively.

Like Fig. 8 and shown in Figure 13; Two tensions with sealing dimensional measurement mechanism 23 with the connected mode of last detent mechanism 21 and following detent mechanism 22 are: two tensions are gone up 2124 one-tenth clearance fit of positioning cylinder extension cylinder with two respectively with two endoporus of going up draw ring 235 of sealing dimensional measurement mechanism 23, and two tensions are extended 2224 one-tenth clearance fit of cylinder with two following positioning cylinders respectively with the endoporus of two following draw rings 236 of sealing dimensional measurement mechanism 23.Like this; When the distance of shaft centers between the outmost surface 2221 of outmost surface 2121 that changes last positioning cylinder 212 and following positioning cylinder 222; Just can be respectively go up under draw ring 235-outer tube joint 237 and the following positioning cylinder 222-238 liang of paths of draw ring 236-inner pipe joint and strain or loosen two extension springs 231, the pulling force that is born between detent mechanism 21 and the following detent mechanism 22 is changed through positioning cylinder 212-on two groups.Notice; Positioning cylinder extends cylinder 2124 and two following positioning cylinders extension cylinders 2224 are that symmetry is extended because two are gone up; So two tensions also are symmetrically distributed with respect to last positioning cylinder 212 and following positioning cylinder 222 median surfaces with sealing dimensional measurement mechanism 23; That is to say that two tensions and sealing dimensional measurement mechanism 23 are that the chi band 1 that is hooked when measuring is symmetrically distributed.

Shown in figure 12; Pulling force confirms that with sealing dimensional measurement mechanism 232 231 methods of bearing pulling force of extension spring are following: at first, measure the distance that outer tube 233 and interior pipe 234 axially slide during this vernier mechanism zero-bit relatively according to the reading of the vernier mechanism in pulling force and the sealing dimensional measurement mechanism 232; Secondly; The pulling force that pairing extension spring 231 is born according to this vernier mechanism zero-bit and the rigidity of extension spring 231 just can be confirmed the pulling force that the pairing extension spring 231 of this any reading of vernier mechanism is born, the pulling force that extension spring 231 is born when just going up detent mechanism 21 and being in any distance with following detent mechanism 22.Can find out, compare, adopt vernier mechanism here, so the tension measurement precision is higher with common spring tension meter pulling force indicating mechanism.

Like Fig. 6 and shown in Figure 12; The method that pulling force and sealing dimensional measurement mechanism 232 confirm to go up distance of shaft centers (sealing size) between the outmost surface 2221 of outmost surface 2121 and following positioning cylinder 222 of positioning cylinders 212 is following: at first, and the distance of sliding when measuring axially relative this vernier mechanism of outer tube 233 zero-bit with interior pipe 234 according to the reading of the vernier mechanism in pulling force and the sealing dimensional measurement mechanism 232; Secondly, get this reading and this vernier mechanism zero-bit pairing on distance of shaft centers sum between the outmost surface 2221 of outmost surface 2121 and following positioning cylinder 222 of positioning cylinder 212 be the sealing size of asking.Because two tensions are symmetrically arranged in chi band 1 both sides of being hooked when measuring with sealing dimensional measurement mechanism 23; When outmost surface 2221 axis of outmost surface 2121 axis of last positioning cylinder 212 and following positioning cylinder 222 are not parallel when actual measurement; Can also adopt two tensions and two pulling force of sealing dimensional measurement mechanism 23 to average, thereby eliminate its influence with the reading that seals the vernier mechanism in the dimensional measurement mechanism 232.

Like Figure 20, Figure 21 and shown in Figure 22, respectively have a buckle pawl surface 311 that is shaped as V-arrangement on two buckle pawls 31 of buckle 3, these two buckle pawl surfaces 311 are arranged face-to-face and are parallel to each other; Buckle pawl 31 hooks chi head 12, and the outside surface 121 that means chi head 12 is tangent with the buckle pawl surface 311 on the buckle pawl 31, like this, just hooks respectively and can these two chi bands 1 be connected in series as if buckle pawl 31 each chi head with two chi bands 1; In order not interfere between belt 11 when buckle pawl 311 hooks chi head 12 and the buckle 31, on buckle 31, to be positioned at 311 places, two buckle pawl surfaces and to have two ringent buckle openings 32.

The method of operating of following illustrative embodiment and principle of work.Method of operating and principle of work when a chi band 1 being set measuring big external diameter as depicted in figs. 1 and 2 at first is described: the first step; Chi band 1 and location tension and sealing dimension measuring device 2 are centered on tested cylindrical 0; Making 1., two chi heads 12 of chi band 1 are hooked with following hook 2211 by last hook 2111 respectively; At this moment, chi band 1 begins to bear the pulling force that two extension springs 231 are applied through last detent mechanism 21 with following detent mechanism 22, thereby fits tightly with tested cylindrical 0 surface; 2. the outmost surface 2221 of outmost surface 2121 and following positioning cylinder 222 that goes up positioning cylinder 212 is surperficial tangent with tested cylindrical 0, simultaneously, and their axis and tested cylindrical 0 parallel axes; Second step, read two pulling force and the reading value that seals in the dimensional measurement mechanism 232, confirm the value of thrust of two extension springs 231; The 3rd step, according to two pulling force and the reading value that seals in the dimensional measurement mechanism 232, the distance of shaft centers (sealing size) between the outmost surface 2121 of definite upward positioning cylinder 212 and the outmost surface 2221 of following positioning cylinder 222; Final step; According to each other geometric relationship of above-mentioned tested cylindrical 0, chi band 1 and location tension and sealing dimension measuring device 2, power that various piece is born such as the mechanical relationship of tension spring tension, self gravitation and friction force etc. and corresponding deformation thereof, and the physical dimension of chi band 1 and location tension and sealing dimension measuring device 2 calculates tested cylindrical 0 external diameter.It may be noted that last hook 2111 and following hook 2211 rotation of proper range as previously mentioned are necessary in order to set up geometric relationship accurately, purpose is to adapt to the tested cylindrical 0 of different-diameter.

Secondly; Method of operating and principle of work when illustrative embodiment such as Fig. 3 and shown in Figure 4 is provided with two chi bands 1 and measures big external diameter: the first step, two chi bands 1, location tension are centered on tested cylindrical 0 with sealing dimension measuring device 2 and buckle 3, making 1., two chi band 1 two adjacent chi heads 12 are hooked respectively by two buckle pawls 31; Thereby they are connected in series; Simultaneously, two chi heads 12 in addition of two chi bands 1 are hooked with following hook 2211 by last hook 2111 respectively, at this moment; Two chi bands 1 begin through last detent mechanism 21, detent mechanism 22 and buckle 3 bear the pulling force that two extension springs 231 are applied down; Thereby fit tightly with tested cylindrical 0 surface, notice, for two chi heads 12 that hooked respectively by two buckle pawls 31 in two chi bands 1; This outside surface 121 that means these two chi heads 12 simultaneously is tangent with tested cylindrical 0 surface respectively; And this point is shown in figure 20, is outside buckle 3, guaranteed with tested cylindrical 0 direction protrusion in opposite directions by the chi head 12 that is hooked by buckle 3; 2. the outmost surface 2221 of outmost surface 2121 and following positioning cylinder 222 that goes up positioning cylinder 212 is surperficial tangent with tested cylindrical 0, simultaneously, and their axis and tested cylindrical 0 parallel axes; Second step, read two pulling force and the reading value that seals in the dimensional measurement mechanism 232, confirm the value of thrust of two extension springs 231; The 3rd step, according to two pulling force and the reading value that seals in the dimensional measurement mechanism 232, the distance of shaft centers (sealing size) between the outmost surface 2121 of definite upward positioning cylinder 212 and the outmost surface 2221 of following positioning cylinder 222; Final step; According to each other geometric relationship of above-mentioned tested cylindrical 0, two chi bands 1, location tension and sealing dimension measuring device 2 and buckle 3, power that various piece is born such as the mechanical relationship of tension spring tension, self gravitation and friction force etc. and corresponding deformation thereof, and two chi bands 1, location tensions calculate tested cylindrical external diameter with the physical dimension of sealing dimension measuring device 2 and buckles 3.

By that analogy, method of operating and principle of work when three or above chi band 1 can illustrative embodiment being set measuring big external diameter, no longer narration.

It may be noted that also can adopt outside measuring appliance such as micrometer inside caliper to measure and confirm in the 3rd step in above method of operating seals size, benefit is that measuring accuracy can increase, and harm is that efficient can descend.

Provide two concrete instances of above-mentioned geometry and mechanical relationship below.At first provide the example when a chi band 1 being set measuring big external diameter: shown in figure 23, suppose that tested cylindrical 0 is in prone position, go up detent mechanism 21 during measurement last, following detent mechanism 22 is down.The diameter of the outmost surface 2221 of the outmost surface 2121 of positioning cylinder 212 and following positioning cylinder 222 is identical on supposing; Be d; Thickness and the width of supposing belt 11 are respectively δ and w; The elasticity modulus of materials of supposing belt 11 is E; Ignore between very little non-full circle

the chi each several part of between chi band 1 and tested cylindrical 0 surface other coefficientoffriction influence and and tested cylindrical 0 surface between friction factor; Ignore the deadweight of influence faint chi band 1 and extension spring 231, have following how much and mechanical relationship:

αu+2β+γ＝2π(1)

$\mathrm{\αu}=\frac{2\mathrm{Lu}+2\mathrm{\ΔLu}+4\mathrm{Ls}-2\sqrt{{(D+d)}^2-{(D+\mathrm{\δ})}^2}}{D+\mathrm{\δ}}---\left(2\right)$

$\mathrm{\β}={\cos }^{-1}\frac{D+\mathrm{\δ}}{D+d}---\left(3\right)$

$\mathrm{\γ}=2{\sin }^{-1}\frac{\mathrm{Lo}}{D+d}---\left(4\right)$

$F1=(P+W1)\sin (\mathrm{\β}+\frac{\mathrm{\γ}}{2})\mathrm{tg\β}+(P+W1)\cos (\mathrm{\β}+\frac{\mathrm{\γ}}{2})---\left(5\right)$

$F2=(P-W2)\sin (\mathrm{\β}+\frac{\mathrm{\γ}}{2})\mathrm{tg\β}-(P-W2)\cos (\mathrm{\β}+\frac{\mathrm{\γ}}{2})---\left(6\right)$

$\frac{F1}{e^{\mathrm{\μ\α}1}}-\frac{F2}{e^{\mathrm{\μ}(\mathrm{\αu}-\mathrm{\α}1)}}=0---\left(7\right)$

$\mathrm{\ΔLu}=\frac{F1\·D}{2\mathrm{\μEw\δ}}(1-\frac{1}{e^{\mathrm{\μ\α}1}})+\frac{F2\·D}{2\mathrm{\μEw\δ}}(1-\frac{1}{e^{\mathrm{\μ}(\mathrm{\αu}-\mathrm{\α}1)}})+\frac{(F1+F2)(\sqrt{{(D+d)}^2-{(D+\mathrm{\δ})}^2}-2\mathrm{Ls})}{2\mathrm{Ew\δ}}---\left(8\right)$

Wherein, D is tested cylindrical 0 diameter, and Lu is the length of chi band 1, and Δ Lu is chi band 1 length deformation after stressed; P is two extension springs, 231 pulling force sums; W1 for comprise in tension and the sealing dimensional measurement mechanism 23 outer tube 233 with the gravity of all parts of upper part and, W2 for tension comprise with sealing dimensional measurement mechanism 23 in pipe 234 all parts of following position gravity and, F1 is that chi band 1 receives pulling force in last hook 2111 places; F2 is that chi band 1 receives pulling force in following hook 2211 places; Lo is the distance of shaft centers (sealing size) between the outmost surface 2221 of outmost surface 2121 and following positioning cylinder 222 of last positioning cylinder 212, when Ls is the measurement state, and the distance of shaft centers between the outside surface 121 of the outmost surface 2121 of last positioning cylinder 212 and the chi head 12 that hooked by last hook 2111; Perhaps, the distance of shaft centers (supposing that they equate) between the outside surface 121 of the outmost surface 2221 of following positioning cylinder 222 and the chi head 12 that is hooked by following hook 2211.

Secondly, provide the example when two chi bands 1 being set measuring big external diameter: shown in figure 24, suppose that tested cylindrical 0 is in prone position, go up detent mechanism 21 during measurement last, following detent mechanism 22 is down.The diameter of the outmost surface 2221 of the outmost surface 2121 of positioning cylinder 212 and following positioning cylinder 222 is identical on supposing; Be d; The diameter of outside surface 121 of chi head 12 of supposing all chi bands 1 is identical; Be dc; The thickness of belt 11 of supposing all chi bands 1 is identical with width, is respectively δ and w, supposes that the elasticity modulus of materials of belt 11 of all chi bands 1 is identical; Be E; Ignore between very little non-full circle

the chi each several part of between chi band 1 and tested cylindrical 0 surface other coefficientoffriction influence and and tested cylindrical 0 surface between friction factor, ignore the deadweight of faint chi band 1, buckle 3 and extension spring 231 of influence, have following how much and mechanical relationship:

$\mathrm{\αu}=\frac{2\mathrm{Lu}+2\mathrm{\ΔLu}+2\mathrm{Ls}-\sqrt{{(D+d)}^2-{(D+\mathrm{\δ})}^2}-\sqrt{{(D+\mathrm{dc})}^2-{(D+\mathrm{\δ})}^2}}{d+\mathrm{\δ}}---\left(10\right)$

$\mathrm{\β}={\cos }^{-1}\frac{D+\mathrm{\δ}}{D+d}---\left(11\right)$

$\mathrm{\γ}=2{\sin }^{-1}\frac{\mathrm{Lo}}{D+d}---\left(12\right)$

$\mathrm{\αv}=\frac{2\mathrm{Lv}+2\mathrm{\ΔLv}+2\mathrm{Ls}-\sqrt{{(D+d)}^2-{(D+\mathrm{\δ})}^2}-\sqrt{{(D+\mathrm{dc})}^2-{(D+\mathrm{\δ})}^2}}{D+\mathrm{\δ}}---\left(13\right)$

$F1=(P+W1)\sin (\mathrm{\β}+\frac{\mathrm{\γ}}{2})\mathrm{tg\β}+(P+W1)\cos (\mathrm{\β}+\frac{\mathrm{\γ}}{2})---\left(17\right)$

$F2=\frac{F1}{e^{\mathrm{\μ\αv}}}---\left(18\right)$

F3＝F2 (19)

$F4=(P-W2)\sin (\mathrm{\β}+\frac{\mathrm{\γ}}{2})\mathrm{tg\β}-(P-W2)\cos (\mathrm{\β}+\frac{\mathrm{\γ}}{2})---\left(20\right)$

$\frac{F3}{e^{\mathrm{\μ\α}1}}-\frac{F4}{e^{\mathrm{\μ}(\mathrm{\αu}-\mathrm{\α}1)}}=0---\left(21\right)$

$\mathrm{\ΔLu}=\frac{F3\·D}{2\mathrm{\μEw\δ}}(1-\frac{1}{e^{\mathrm{\μ\α}1}})+\frac{F4\·D}{2\mathrm{\μEw\δ}}(1-\frac{1}{e^{\mathrm{\μ}(\mathrm{\αu}-\mathrm{\α}1)}})+\frac{F3\sqrt{{(D+\mathrm{dc})}^2-{(D+\mathrm{\δ})}^2}}{2\mathrm{Ew\δ}}$

$+\frac{F4(\sqrt{{(D+d)}^2-{(D+\mathrm{\δ})}^2}-2\mathrm{Ls})}{2\mathrm{Ew\δ}}---\left(22\right)$

$\mathrm{\ΔLv}=\frac{F2\·D}{2\mathrm{\μEw\δ}}(1-\frac{1}{e^{\mathrm{\μ\αv}}})+\frac{F2\sqrt{{(D+\mathrm{dc})}^2-{(D+\mathrm{\δ})}^2}}{2\mathrm{Ew\δ}}+\frac{F1(\sqrt{{(D+d)}^2-{(D+\mathrm{\δ})}^2}-2\mathrm{Ls})}{2\mathrm{Ew\δ}}---\left(23\right)$

Wherein, D is tested cylindrical 0 diameter, and Lu is the length of the chi band 1 that links to each other with following detent mechanism 22; Δ Lu is this chi band 1 length deformation after stressed; F4 receives pulling force for this chi band 1 in following hook 2211 places, and F3 receives pulling force for this chi band 1 in buckle 3 places, and Lv is the length of the chi band 1 that links to each other with last detent mechanism 21; Δ Lv is this chi band 1 length deformation after stressed; F2 receives pulling force for this chi band 1 in buckle 3 places, F1 receives pulling force for this chi band 1 in last hook 2111 places, and P is two extension springs, 231 pulling force sums; W1 for comprise in tension and the sealing dimensional measurement mechanism 23 outer tube 233 with the gravity of all parts of upper part with; W2 for tension comprise with sealing dimensional measurement mechanism 23 in pipe 234 all parts of following position gravity and, Lo is the distance of shaft centers (sealing size) between the outmost surface 2221 of outmost surface 2121 and following positioning cylinder 222 of last positioning cylinder 212, when Ls is the measurement state; Distance of shaft centers between the outside surface 121 of the outmost surface 2121 of last positioning cylinder 212 and the chi head 12 that hooked by last hook 2111; Perhaps, the distance of shaft centers (supposing that they equate) between the outside surface 121 of the outmost surface 2221 of following positioning cylinder 222 and the chi head 12 that is hooked by following hook 2211, Luv are the distance of shaft centers between the outside surface 121 of two chi heads 12 being hooked of two buckle pawls 31.

Can be obvious according to the foregoing description; With respect to the chi band in the background technology; Embodiment has taked two main measures to improve performance: the one, introduced two positioning cylinders (going up the outmost surface 2121 of positioning cylinder 212 and the outmost surface 2221 of following positioning cylinder 222); Make in background technology the gap between two right angle angle bar will measuring become in non-full circle

chi distance of shaft centers between two parallel cylinders; So; As long as the diameter of these two cylinders is selected enough greatly; Just can increase the distance of shaft centers between these two cylinders that to survey greatly, thereby increase the big outside diameter measuring scope of single chi band 1 pairing non-full circle

chi greatly; The 2nd, be provided with and can measure big external diameter, because the combined effect of the chi band 1 of different length can significantly reduce and measure the tested external diameter of a certain scope (like the quantity of 1～6m) needed chi band 1 more than one 1 on-the-spot connection of chi band.For example, saying approx, is six chi bands 1 of 1m, 2m, 3m, 4m, 5m and 6m like the former length that needs, and only needs three chi bands 1 of 1m, 2m and 3m after the combination, because the chi band 1 of 4m, 5m and 6m can be connected by the chi band 1 of 1m, 2m and 3m.In addition; The on-the-spot distance of shaft centers of accurately measuring between two parallel cylinders is also much easier than the gap between two right angle angle bar measuring non-equidistance, and embodiment adopts pulling force directly to draw this distance of shaft centers with sealing dimensional measurement mechanism 232 then further to have simplified this operation.At last; Different with tradition

chi in the background technology or chi band is; The power that chi band 1 is born among the embodiment needs not be constant force; Go up the introducing of hook 2111, following hook 2211 and buckle pawl 31, the operation of device is easier in addition.

Claims (6)

1. a non-full circle Π chi that is used for big outside diameter measuring is characterized in that, this non-full circle Π chi comprises one ruler band (1), a location tension at least and seals dimension measuring device (2);

The flexible strap (11) that it is rectangle that said chi band (1) comprises a cross section and two chi heads (12) that are connected to belt (11) two ends; The outside surface (121) of chi head (12) is cylindrical; After belt (11) is stretching; Belt (11) is corresponding to the center line of its square-section line of centres and outside surface (121) intersect vertical axis of two chi heads (12), and belt (11) is corresponding to the surface on long limit, its square-section and outside surface (121) parallel axes of two chi heads (12);

The tension of said location comprises one with sealing dimension measuring device (2) and goes up detent mechanism (21), a following detent mechanism (22) and at least one tension and sealing dimensional measurement mechanism (23); Last detent mechanism (21) comprises one and goes up positioning cylinder (212), one and have the going up of rise to the bait (211) of the last hook (2111) that hooks chi head (12), an axle shape spool (213) and at least two and be the head bearing of rolling bearing (214); The outmost surface (2121) of last positioning cylinder (212) is cylindrical; Outside surface (121) parallel axes of its axis and the chi head (12) that is hooked by last hook (2111); Last positioning cylinder (212) inner packet contains two last positioning cylinder endoporus (2122) coaxial with the outmost surface (2121) of last positioning cylinder (212); At the last positioning cylinder window (2123) that has a window-like on these two between the positioning cylinder endoporus (2122); Head bearing (214) is installed in two respectively and goes up in the positioning cylinder endoporus (2122); Last axle (213) is installed in head bearing (214) endoporus, and rise to the bait (211) then are connected with last axle (213) and make the last hook (2111) on it be exposed to positioning cylinder (212) outside through last positioning cylinder window (2123); Said down detent mechanism (22) comprises lower shaft (223) and at least two that a following positioning cylinder (222), have the following hook (221) of the following hook (2211) that hooks chi head (12), an axle shape and is the lower bearing of rolling bearing (224); The outmost surface (2221) of following positioning cylinder (222) is cylindrical; Outside surface (121) parallel axes of the chi head (12) that hook (2211) hooks under its axis and the quilt; Following positioning cylinder (222) inner packet contains two following positioning cylinder endoporus (2222) coaxial with the outmost surface (2221) of following positioning cylinder (222); Between these two following positioning cylinder endoporus (2222), have the following positioning cylinder window (2223) of a window-like; Lower bearing (224) is installed in respectively in two following positioning cylinder endoporus (2222); Lower shaft (223) is installed in lower bearing (224) endoporus, and following hook (221) then is connected with lower shaft (223) and makes the following hook (2211) on it be exposed to down positioning cylinder (222) outside through following positioning cylinder window (2223); Said tension comprises an extension spring (231), a pulling force and sealing dimensional measurement mechanism (232), a last draw ring (235) that is connected with last detent mechanism (21) and a following draw ring (236) that is connected with following detent mechanism (22) of confirming this extension spring (231) pulling force that bears with sealing dimensional measurement mechanism (23); The said mutual relationship that goes up between detent mechanism (21), following detent mechanism (22) and tension and the sealing dimensional measurement mechanism (23) is: tension and sealing dimensional measurement mechanism (23) are positioned between detent mechanism (21) and the following detent mechanism (22) and also through last draw ring (235) on it and following draw ring (236) they are linked together respectively, are parallel to each other between outmost surface (2221) axis of outmost surface (2121) axis of last positioning cylinder (212) and following positioning cylinder (222).

2. the non-full circle Π chi that is used for big outside diameter measuring as claimed in claim 1; It is characterized in that; The syndeton of said belt (11) and chi head (12) is: on chi head (12), have a flat hole (122) perpendicular to chi head (12) outside surface (121) axis; The xsect in this flat hole (122) has two parallel long limits; These two long limits are symmetrical in outside surface (121) axis of chi head (12), and its distance is provided with the counterbore (124) of screw hole (123) and correspondence greater than the thickness of belt (11) perpendicular to the axis of this flat hole (122) and chi head (12) outside surface (121); Each end in belt (11) two ends, with the corresponding position of screw hole (123); Be provided with unthreaded hole (111), belt (11) and these two the chi heads (12) that inserted respectively in the flat hole (122) by belt (11) that insert respectively in the flat holes of two chi heads (12) (122) at two ends are fixed together by the screw (13) through unthreaded hole (111) screw-in screw hole (123) respectively.

3. the non-full circle Π chi that is used for big outside diameter measuring as claimed in claim 1; It is characterized in that; Said rising to the bait (211) is exposed to the last hook (2111) that the outside end of positioning cylinder (212) is provided with the last hook surface (21111) that is shaped as V-arrangement; Last hook (2111) hooks chi head (12); The outside surface (121) of chi head (12) is tangent with last hook surface (21111), on rise to the bait (211), is positioned at the pawl surface (21111) of rising to the bait and locates to have a ringent opening of rising to the bait (2112); Said hook (221) down is exposed to down the following hook (2211) that the outside end of positioning cylinder (222) is provided with the following hook surface (22111) that is shaped as V-arrangement; Following hook (2211) hooks chi head (12); The outside surface (121) of chi head (12) is tangent with following hook surface (22111), and a ringent hook opening (2212) is down located to have in hook surface (22111) under being positioned on the following hook (221).

4. the non-full circle Π chi that is used for big outside diameter measuring as claimed in claim 1; It is characterized in that; Said tension comprises extension spring (231), outer tube (233), interior pipe (234), last draw ring (235), following draw ring (236), outer tube joint (237) and inner pipe joint (238) with sealing dimensional measurement mechanism (23); Wherein, Outer tube (233) and interior pipe (234) are all a pipe that contains coaxial inner and cylindrical; Last draw ring (235) and following draw ring (236) are all an annulus that contains coaxial inner and cylindrical, and last draw ring (235) cylindrical is littler than outmost surface (2121) diameter of last positioning cylinder (212), and following draw ring (236) cylindrical is littler than outmost surface (2221) diameter of following positioning cylinder (222); Tension with the annexation of sealing dimensional measurement mechanism (23) various piece is: outer tube (233) cylindrical and interior pipe (234) the endoporus clearance fit for axially sliding relatively; Last draw ring (235) is connected with outer tube joint (237); Outer tube joint (237) is connected with outer tube (233); Outer tube joint (237) is connected with an end of extension spring (231); The other end of extension spring (231) is connected with inner pipe joint (238), and interior pipe (234) is connected with inner pipe joint (238), and inner pipe joint (238) is connected with following draw ring (236).

5. the non-full circle Π chi that is used for big outside diameter measuring as claimed in claim 4; It is characterized in that; Have on the said outer tube (233) window-like outer window of tube (2331) and with vernier groove its next-door neighbour, that be plane surface (2332); (2332) upper edge outer tube (233) endoporus axially engraves vernier groove (2333) on vernier groove surface; Pipe (234) cylindrical axially is carved with main scale groove (2341) in the upper edge, position that interior pipe (234) cylindrical comes out through outer window of tube (2331), and vernier groove (2333) and main scale groove (2341) and the outer tube (233) that carries them and interior pipe (234) constitute one jointly for the pulling force of vernier mechanism and seal dimensional measurement mechanism (232).

6. the non-full circle Π chi that is used for big outside diameter measuring as claimed in claim 1 is characterized in that, when two and above chi band (1) are set, the buckle (3) that quantity is less than set chi band (1) quantity 1 are set set chi band (1) is connected in series; Said buckle (3) is provided with two buckle pawls (31), and the adjacent chi head (12) of two adjacent chi bands (1) is hooked in together, and outside surface (121) axis of these two chi heads (12) is parallel to each other; Respectively have a buckle pawl surface (311) that is shaped as V-arrangement on said two buckle pawls (31), these two buckle pawl surfaces (311) are arranged face-to-face and are parallel to each other; Buckle pawl (31) hooks chi head (12), and the outside surface (121) of chi head (12) is tangent with the buckle pawl surface (311) on the buckle pawl (31); On buckle (31), be positioned at two buckle pawl surfaces (311) and locate to have two ringent buckle openings (32).

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