Description

GAP MEASURING APPARATUS

Technical Field

[1] The present invention relates, in general, to gap measuring apparatuses which are used to measure gaps and, more particularly, to a gap measuring apparatus which measures the distance between two objects or measures the inner diameter of an object. Background Art

[2] As well known to those skilled in the art, in conventional arts, users manually measure gaps of objects using vernier calipers or micrometers.

[3] However, in the case where a user manually measures a gap of an object, even if the user is highly skilled, very precise measurement may not be possible. Hence, there are problems in that the reliability of the measured data is low and the measuring operation is inconvenient.

[4] In an effort to overcome the above problems, recently, various studies haven been conducted into methods of measuring gaps precisely and conveniently. FIG. 1 illustrates a representative example of a gap measuring apparatus proposed to achieve the above-mentioned purpose.

[5] As shown in FIG. 1, in the gap measuring apparatus, gap measuring apparatuses 20,

20' are vertically installed in a support body 10 such that gap measuring parts 22 and 22' of the gap measuring apparatuses 20 and 20' protrude upwards outside a base plate 11 of the support body 10. As required, several gap measuring apparatuses 20 and 20' can be provided in the support body 10. Here, the lengths of the portions of the gap measuring parts 22 and 22' which protrude outside the base plate differ from each other.

[6] A method of measuring the inner diameter of a neck part of an object P using the conventional gap measuring apparatus 20, 20' will be described in brief with reference to FIGS. 2 and 3.

[7] As shown in FIG. 2, a user holds the object P to be measured and brings it into contact with the base plate 11 of the support body 10 such that the gap measuring part 22 of the gap measuring apparatus 20, which is disposed to the left when seen in FIG. 1, is inserted into the neck part of the object P. As such, when the object P is brought into contact with the base plate 11 such that the gap measuring part 22 is inserted into the neck part, a movable probe 22b, which is elastically supported such that it is biased in one direction, is pushed, and a stationary probe 22a and the movable probe 22b are brought into close contact with the inner surface of the neck part of the object P. Then, the inner diameter of the object P is automatically calculated depending on the degree

to which the movable probe 22b is pushed inwards. The calculated inner diameter of the neck part of the object P is output through a display 21 to make the user aware of it.

[8] Thereafter, the object P is removed and, as shown in FIG. 3, an inner diameter of a deeper portion of the neck part of the object P is measured in the same manner as in the above operation.

[9] Because the conventional gap measuring apparatus 20, 20' is operated in a semiautomatic manner, the measuring operation is simplified compared to the method of manually measuring the gap of the object P using the vernier caliper or micrometer. Furthermore, because the measured inner diameter is automatically output through the display 21, 21', the user is prevented from incorrectly reading the scale. However, the user must directly handle the object P as before. In addition, the range within which measurement is allowed is restricted, so that the object P which can be measured is very restricted.

[10] As well as the gap measuring apparatus 20, 20', several gap measuring apparatuses using other methods have been proposed. However, because these gap measuring apparatuses have very complex structures, and because measurement precision is still limited, they are not widely used. Disclosure of Invention Technical Problem

[11] Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a gap measuring apparatus which is able to automatically conduct a gap measuring process and to measure a gap of an object more precisely.

Advantageous Effects

[12] As described above, a gap measuring apparatus of the present invention holds an object P, which has been set at a correct position at which a gap thereof is measured, using suction force and, thereafter, measures an inner diameter of a neck part of the object P using first probes 712a and 712b. That is, the distance between the first probes 712a and 712b is photographed by the image photographing apparatus, and the image thereof is thereafter processed. Thereby, the inner diameter of the neck part of the object P is measured. Because these processes are automatically conducted, the inner diameter measuring operation is very convenient.

[13] Particularly, because the inner diameter of the neck part of the object P is measured by photographing the distance between the first probes 712a and 712b, if the gap measuring apparatus 700 malfunctions, this can be immediately detected. Therefore, the reliability of the measured data is markedly increased, and repair and maintenance are convenient.

Brief Description of the Drawings

[14] FIG. 1 is a view showing a conventional gap measuring apparatus;

[15] FIGS. 2 and 3 are views illustrating the use of the conventional gap measuring apparatus; [16] FIG. 4 is a view showing a gap measuring apparatus installed in a specific apparatus, according to the present invention;

[17] FIG. 5 is a partially sectional view of the shape measuring apparatus of FIG. 4;

[18] FIG. 6 is an exploded perspective view showing an important part of the gap measuring apparatus according to the present invention; [19] FIGS. 7 through 9 are views showing the gap measuring apparatus holding a neck part of an object using suction force according to the present invention; [20] FIGS. 10 and 11 are views illustrating a process of measuring a gap of the object using first probes according to the present invention;

[21] FIGS. 12 and 13 are, respectively, plan views corresponding to FIGS. 10 and 11;

[22] FIG. 14 is a view corresponding to FIG. 6, but showing a gap measuring apparatus according to a second embodiment of the present invention; [23] FIGS. 15 and 16 are views respectively corresponding to FIGS. 12 and 13, but showing a process of measuring the gap of the object using first and second probes; [24] FIGS. 17 and 18 are views respectively corresponding to FIGS. 10 and 11, but showing a process of measuring the gap of the object using the second probes; [25] FIG. 19 is a view corresponding to FIG. 9, but showing a second gap measuring process using the gap measuring apparatus according to the present invention; and [26] FIG. 20 is a view corresponding to FIG. 10, but showing the second gap measuring process using the gap measuring apparatus according to the present invention. [27] -Description of the elements in the drawings-

[28] 10; support body, 11; base plate,

[29] 20,20'; gap measuring apparatus, 21, 21'; display,

[30] 22,22'; gap measuring part, 22a, 22a'; stationary probe,

[31] 22b,22b'; movable probe, 40; support body,

[32] 52; spacer, 53; guide

[33] 91,92,93,94,95,96,97; sealing O-ring,

[34] 100; base, 200; object carrying apparatus,

[35] 300; image photographing apparatus, 310; camera

[36] 320; screen, 400; camera moving apparatus,

[37] 410; first moving unit, 420; second moving unit,

[38] 500; object supply apparatus, 511,512; guide rail,

[39] 520; object input control unit, 700; gap measuring apparatus,

[40] 710; gap measuring apparatus body, 710a; insert part,

[41] 711a; support block, 71 Ib; movable block body,

[42] 711b'; camera coupling member, 711b"; cover,

[43] 711c; upper cover, 71 Id; lower cover,

[44] 712a,712b; first probe, 713a,713b; second probe,

[45] 720; image photographing unit, 721; camera,

[46] 721a; lens, 721b; light source connection part,

[47] 722; screen, 800; gap measuring apparatus moving apparatus,

[48] ALla,ALlb,ALlc,ALld; releasable object holding air line,

[49] AL2a,AL2b,AL2c,AL2d; probe drive air line,

[50] AL3a,AL3b; movable block drive air line,

[51] P; object,

[52] PST; piston part

Best Mode for Carrying Out the Invention

[53] In order to accomplish the above object, the present invention provides a gap measuring apparatus, comprising: a gap measuring apparatus body, including a housing having on a lower end thereof an insert part that is removably inserted into a portion of an object at which a gap is to be measured, and a pair of first probes provided in the insert part at diametrically opposite positions on a horizontal straight line, with a releasable object holding air line formed in the housing to hold the object using suction force and being open at a predetermined position of the insert part, and a probe drive air line formed in the housing to reciprocally move at least one probe, wherein some air line sections of the releasable object holding air line are vertically formed in the housing, thus being used as a space for photographing images of the probes, and inner ends of the first probes are exposed into the image photographing air line sections; and an image photographing unit installed in the housing of the gap measuring apparatus body, and including a camera to photograph the inner ends of the first probes exposed into the image photographing air line sections, thus measuring a distance between the first probes, and a screen provided in the housing of the gap measuring apparatus body below the first probes. Mode for the Invention

[54] Hereinafter, the present invention will be described in detail with reference to the attached drawings.

[55] FIGS. 4 and 5 show a gap measuring apparatus of the present invention, which is installed in a specific apparatus, and, in detail, show the gap measuring apparatus installed in a shape measuring apparatus, which measures the outer shape of an object P. The operation of the shape measuring apparatus will be explained in brief herein

below.

[56] First, a user manually inputs objects P to be measured into guide rails 511 and 512 of an object supply apparatus 500, thus preparing for the shape measuring operation.

[57] In this state, the shape measuring apparatus is operated. Then, a first object P slides along the inclined guide rails 511 and 512 in response to the operation of an object input control unit 520 of the object supply apparatus 500, and is thus supplied to an object carrying apparatus 200.

[58] Thereafter, the object carrying apparatus 200 is operated, thus carrying and rotating the object P such that the object P is correctly placed at a desired image photographing position and is set at a desired image photographing angle.

[59] As such, after the object P has been placed at the desired image photographing position and set at the desired image photographing angle, a camera 310 constituting an image photographing apparatus 300 partially photographs several portions of a neck part of the object P while the position thereof is changed.

[60] After the process of photographing the neck part of the object P has been completed, the gap measuring apparatus of the present invention is automatically moved by a gap measuring apparatus moving apparatus 800 to a desired position, and the inner diameter of the neck part of the object P is measured.

[61] After the process of measuring the inner diameter of the neck part of the object P has been completed, the object P is carried by the object carrying apparatus 200 in the direction in which the operation progresses, and is discharged outside.

[62] Referring to FIGS. 6 and 7, the gap measuring apparatus 700 of the present invention includes a gap measuring apparatus body 710 and an image photographing unit 720.

[63] The gap measuring apparatus body 710 includes a housing, which has on a lower end thereof an insert part 710a that is removably inserted into a desired portion of the object P at which a gap is measured, and a pair of first probes 712a and 712b, which are provided in the insert part 710a at diametrically opposite positions on the same horizontal straight line. A releasable object holding air line ALIa, ALIb, ALIc and ALId, which holds the object P using suction force, is formed in the housing and is open at a predetermined position of the insert part. Furthermore, a probe drive air line AL2a and AL2b, which reciprocally moves at least one probe 712b, is formed in the housing. Some air line sections ALIb and ALIc of the releasable object holding air line ALIa, ALIb, ALIc and ALId are vertically formed in the housing, thus being used as space for photographing a probe image. The inner ends of the first probes 712a and 712b are exposed into the air line sections ALIb and ALIc for image photographing. In this embodiment, one probe 712a of the first probes 712a and 712b is securely fixed to the insert part 710a by a screw coupling method, while the other

probe 712b is installed in the insert part 710a of the housing of the gap measuring apparatus body so as to be movable using pressure supplied through the probe drive air line AL2a and AL2b. In this case, the fixed first probe 712a is constructed such that an end thereof must be exposed outside the insert part 710a of the housing.

[64] The image photographing unit 720 is installed in the housing of the gap measuring apparatus body 710. The image photographing unit 720 includes a camera 721, which photographs the inner ends of the first probes 712a and 712b, which are exposed into the image photographing air line sections ALIb and ALIc, thus measuring the distance between the first probes 712a and 712b. The image photographing unit 720 further includes a screen 722, which is provided in the housing of the gap measuring apparatus body 710 below the first probes 712a and 712b.

[65] The operation of the gap measuring apparatus of the present invention will be described with reference to FIGS. 5 and 7 through 11.

[66] As shown in FIGS. 5 and 7, in the state in which the gap measuring apparatus 700 is lifted to top dead center by the gap measuring apparatus moving apparatus 800, when the object P is set at a gap measuring position {in this embodiment, this is the same as the image photographing position}, the gap measuring apparatus 700 is moved downwards to bottom dead center, so that, as shown in FIG. 8, the insert part 710a of the gap measuring apparatus 700 is inserted into the neck part of the object P.

[67] In this state, vacuum pressure is applied through the releasable object holding air line ALIa, ALIb, ALIc and ALId of the housing. Then, outside air is forcibly drawn into the housing through the releasable object holding air line ALIa, ALIb, ALIc and ALId, which is open through the insert part 710a, so that, as shown in FIG. 9, the object P is moved upwards and attached to the housing of the gap measuring apparatus 700 by the suction force. FIG. 10 is a sectional view showing an enlargement of an important part of FIG. 7c.

[68] In this state, static pressure is supplied through the probe drive air line AL2a and

AL2b. Then, the first probe 712b of the pair of first probes 712a and 712b, which is connected to the probe drive air line AL2a and AL2b, is forcibly moved outwards by the static pressure supplied through the probe drive air line AL2a and AL2b and is thus brought into contact with the inner surface of the neck part of the object P. Here, the first probe 712b pushes the inner surface of the neck part of the object P in one direction until the distance between the first probes 712a and 712b is maximized. Therefore, the center of the neck part of the object P and the center of the insert part 710a are naturally aligned. The sum of the lengths of the first probes 712a and 712b and the distance dlO' (see, FIG. 13) therebetween becomes equal to the inner diameter of the neck part of the object P.

[69] Meanwhile, as shown in FIGS. 12 and 13, the camera 721 photographs both the first

probes 712a and 712b, which are exposed through the image photographing air line sections ALIb and ALIc, and distances dlO and dlO' between the first probes 712a and 712b through a lens 721a. This image is processed to measure the inner diameter of the neck part of the object P.

[70] In the preset invention, the object P is set at the correct gap measuring position by suction force, and the inner diameter of the neck part of the object P is measured through the first probes 712a and 712b. That is, the distance between the first probes 712a and 712b is photographed by the image photographing apparatus, and this is thereafter processed. Thereby, the inner diameter of the neck part of the object P is measured. Because these processes are automatically conducted, the inner diameter measuring operation is very convenient.

[71] Particularly, because the inner diameter of the neck part of the object P is measured by photographing the distance between the first probes 712a and 712b, even if the gap measuring apparatus 700 malfunctions, this can be immediately detected. Therefore, the reliability of the measured data is markedly increased, and repair and maintenance are convenient.

[72] When required, as shown in FIGS. 14 through 16, a pair of second probes 713a and

713b, which are horizontally arranged at diametrically opposite positions, may be provided in the insert part 710a of the housing at positions spaced apart from the first probes 712a and 712b at 90°. Here, a probe drive air line AL2a, AL2b and AL2d (reference character AL2d is referred to in FIG. 19) for reciprocally moving at least one first probe 712b and the second probes 713a and 713b is formed in the housing. The inner ends of the first probes 712a and 712b and the second probes 713a and 713b are exposed into the image photographing air line section ALIb and ALIc of the releasable object holding air line. In this case, as shown in FIGS. 15 and 16, inner diameters (two values) of two portions of the neck part of the object P which are spaced apart from each other by 90° can be measured at the same time using the first probes 712a and 712b and the second probes 713a and 713b even though only one measuring operation is conducted. In this embodiment, as shown in FIGS. 42a and 42b, both second probes 713a and 713b are reciprocally movable, unlike the first probes 712a and 712b.

[73] Furthermore, as shown in FIGS. 7 through 9, the housing of the gap measuring apparatus body 710 includes a cylindrical support block 711a, which is provided in the gap measuring apparatus moving apparatus 800 through separate coupling members 16 and 17. An air line inlet AL2a and a guide air line AL2c, which constitute the probe drive air line, and movable block drive air lines AL3a and AL3b are formed in the circumferential surface of the support block 71 Ia. The housing of the gap measuring apparatus body 710 further includes a movable block, which is movably inserted in the

support block 71 Ia. The insert part 710a, which is removably inserted into the desired portion of the object P at the position where the gap is measured, is provided under the lower end of the movable block. A piston part PST, which is in airtight contact with the inner surface of the support block 71 Ia, is provided at an intermediate position in the movable block, and compression spaces Sl and S2, which respectively communicate with the movable block drive air lines AL3a and AL3b, are respectively formed in the movable block at upper and lower positions of the piston part PST. In addition, the releasable object holding air line ALIa, ALIb, ALIc and ALId and a probe drive line section AL2b of the probe drive air line are formed in the movable block. The housing of the gap measuring apparatus body 710 further includes an upper cover 711c, which is provided on the upper end of the support block 71 Ia to prevent the movable block 71 Ib, 71 Ib' and 71 Ib" from being undesirably removed outside the upper end of the support block and to close the upper compression space Sl. The housing of the gap measuring apparatus body 710 further includes a lower cover 71 Id, which is provided under the lower end of the support block 71 Ia to prevent the movable block 71 Ib, 71 Ib' and 71 Ib" from being undesirably removed outside the lower end of the support block and to close the lower compression space S2. Thus, the movable block is reciprocally movable between top dead center and bottom dead center using pressure supplied through the movable block drive air lines AL3a and AL3b. In the state of FIG. 9, that is, in the state in which static pressure is applied into the compression space S2 through the lower movable drive air line AL3b so that the movable block is lifted upwards, a first operation of measuring the inner diameter of a portion of the neck part of the object P is conducted. Thereafter, when static pressure is applied into the compression space Sl through the upper movable drive air line AL3a, as shown in FIGS. 19 and 20, the movable block is moved from the top dead center to the bottom dead center, so that the insert part 710a, the first probes 712a and 712b and the second probes 713a and 713b are inserted into the neck part of the object P to a deeper position. In this state, a second operation of measuring the diameter of another portion of the neck part of the object P is conducted. According to this embodiment, in the state in which the object P is held by suction force, the inner diameters of several portions of the neck part of the object P can be consecutively measured depending on the depth.

[74] In the case of this embodiment, as shown in FIG. 19, the movable block includes a movable block body 71 Ib, which is movably inserted into the support block 711a. The insert part 710a, which is removably inserted into the desired portion of the object P at which a gap is measured, is provided under the lower end of the movable block body 71 Ib. The piston part PST, which is in airtight contact with the inner surface of the support block 71 Ia, is provided at an intermediate position in the movable block body

711a, and the compression spaces Sl and S2, which respectively communicate with the movable block drive air lines AL3a and AL3b, are respectively formed in the movable block body 71 Ia at upper and lower positions of the piston part PST. In addition, a second image photographing air line section ALIc of the releasable object holding air line is vertically formed through the movable block body 71 Ib. An air line suction inlet ALId of the releasable object holding air line communicates with the second image photographing air line section ALIc and is horizontally formed through the insert part 710a. The movable block further includes a camera coupling member 71 Ib', which is removably coupled to the upper end of the movable block body 71 Ib. A first image photographing air line section ALIb of the releasable object holding air line is vertically formed through the camera coupling member 71 Ib'. An air line discharge hole ALIa of the releasable object holding air line communicates with the first image photographing air line section ALIb and is horizontally formed through the camera coupling member 71 Ib'. The movable block further includes a cover 71 Ib", which is mounted to the lower end of the movable block body 71 Ib to close the open lower end of the second image photographing air line section ALIc. As such, the movable block according to the embodiment consists of three elements 71 Ib, 71 Ib' and 71 Ib", which are manufactured through separate processes. Therefore, although it is inconvenient to assemble the three elements, there is an advantage in that it is relatively easy to manufacture them so that the movable block can be manufactured at a low cost.

[75] Furthermore, the embodiment of the present invention is characterized in that, because the upper surface of the cover 71 Ib" is surface-treated to have a smooth and even surface, it serves as the screen 722 of the image photographing unit 720. As such, if the upper surface of the cover 71 Ib", which has been surface-treated to have a smooth and even surface, is used as the screen 722, there is an advantage in that the number of parts is reduced. Of course, when necessary, a screen 722, which is manufactured through a separate process, may be provided on the upper surface of the cover 71 Ib". As illustrated in this embodiment, in the case where a reflective surface is used as the screen 722, a light source connection part 721b (see, FIG. 6 or 14) is coupled to the camera 721, and a light supply line is connected between an illuminator (not shown) and the light source connection part 721b. Thus, the light of the illuminator is radiated through the lens 721a, both onto the inner ends of the probes 712a, 712b, 713a and 713b, which are exposed through the image photographing air line sections ALIb and ALIc, and onto the screen 722, which is disposed behind the probes. However, as required, a backlight (not shown) may be used as the screen 722. In the case where the backlight is used as the screen 722, the light supply line must be connected to the screen 722 rather than being connected to the camera 721.

[76] Meanwhile, in FIGS. 6 through 20, reference numerals 91, 92, 93, 94, 95, 96 and 97

denote O-rings for sealing, 52 denotes a spacer, and 53 denotes a guide.

[77] The present invention is not limited to the above-mentioned embodiments, and those skilled in the art will appreciate that various modifications, additions and substitutions are possible, without departing from the scope and spirit of the invention as disclosed in the accompanying claims.

[78] For example, in the above-mentioned embodiments, although a perform, which is an intermediate product of a PET bottle, has been illustrated as the object P and the gap measuring apparatus 700 of the present invention has been illustrated as being used to measure the inner diameter of the neck part of the object P, the gap measuring apparatus of the present invention is not limited to being used to measure any particular object or particular part, but can be used to measure a gap in any object or part.