CN102621175B - Measurement device for thermal shrinkage ratio of pull wire - Google Patents

Abstract

The invention discloses a measuring device for the heat shrinkage rate of a cable. The measuring principle is as follows: first, the cable is properly tensioned by an electric platform, and the original length of the cable is recorded as L by a displacement sensor, and then the electric platform moves to make the cable in a relaxed state, and the Put the cable into the oven and heat it for a period of time. After taking out the cable and cooling it to the test environment temperature, the electric platform moves to make the cable tension to the same degree. The length S of the cable at this time is recorded by the displacement sensor. According to the calculation formula of thermal shrinkage ε=( L－S)/L×100%, the thermal shrinkage rate of the pull wire can be calculated. The invention innovatively proposes a method in which the electric platform drives the cable to move, uses a tension sensor to measure the tension on the cable, and uses a displacement sensor to measure the length change of the cable, thereby realizing automatic measurement of the heat shrinkage rate of the cable.

Description

A measuring device for heat shrinkage rate of drawing wire

technical field

The invention relates to the technical field of cigarette draw wire detection, in particular to a measuring device for the heat shrinkage rate of draw wires.

Background technique

Cigarette pull string is not only a tool to help consumers open the outer film of cigarettes, but also one of the important means of anti-counterfeiting for cigarette companies. According to statistics, more than 90% of the world's film-wrapped cigarettes use wire drawing technology. The performance of the drawing wire, especially the characteristics of heat shrinkage, has an important impact on the appearance of the cigarette wrapping film. An appropriate heat shrinkage rate can make the cigarette wrapper have a tighter and more uniform wrapping property, and avoid the problems of wrinkles on the package cover and incomplete packaging.

The essence of the pull wire is a film with pressure-sensitive adhesive, and its heat shrinkage test method is similar to that of the film. There is no standard for the current test method of heat shrinkage rate of draw wire, and the actual test method refers to the test standard of YC-266 "Packaging Film for Cigarettes". The heat shrinkage test method of the film specified in YC-266 "Packaging Film for Cigarettes" is: first take a sample and measure the original size with a ruler, heat it in the oven for a period of time, take it out and cool it to the test environment temperature, measure the size after heat shrinkage, and calculate its heat shrinkage. The defects of this testing method mainly include: 1. The degree of automation is low, the operation is complicated, and the heat shrinkage rate of the pull wire cannot be automatically calculated and recorded, and the efficiency is low; 2. The manual measurement error is relatively large; 3. The test uses a general-purpose oven, an oven Too big.

At the same time, there are also some problems in the actual test process of the heat shrinkage rate of the drawn wire, because the standard is mainly aimed at the film used for cigarette packaging, and the drawn wire has its own characteristics, its width is very narrow, and it is relatively soft. In the process, it is easy to wrinkle, twist, and deform seriously, so it is difficult to measure the size accurately. In the actual measurement process, the cable is usually straightened and tensioned before measurement, but the process of tensioning the cable is manual operation, and it is difficult to ensure that the tension on the cable is consistent, so the measured data is inaccurate. How to achieve accurate and fast The measurement of the heat shrinkage of the drawing wire is an urgent problem in the industry.

Contents of the invention

The purpose of the present invention is to solve the existing technical difficulties in view of the current situation of difficulty in measuring the thermal shrinkage rate of cigarette draw wires, and provide an accurate and reliable measuring device for the thermal shrinkage rate of draw wires in compliance with industry standards.

The measurement principle of the present invention is as follows: first, the cable is properly tensioned by the electric platform, and the original length of the cable is recorded as L by a displacement sensor, and then the electric platform moves to make the cable in a relaxed state, and the cable is put into an oven to heat for a period of time, and then the cable is taken out to cool After reaching the test environment temperature, the electric platform moves to make the cable tension to the same degree, and the length S of the cable at this time is recorded by the displacement sensor. According to the calculation formula of thermal shrinkage ε= (L－S) /L×100%, it can be calculated The heat shrinkage of the drawing wire.

The present invention achieves the above object through the following schemes:

A measuring device for the heat shrinkage rate of a drawing wire, comprising a measuring unit and an oven, the measuring unit comprising a moving assembly, an electric platform, a tension sensor, a displacement sensor, a fixed door of the oven, a left clamp and a right clamp;

The electric platform and the fixed door of the oven are fixed on the moving component and pushed by the moving component;

The displacement sensor and tension sensor are fixed on the electric platform;

A hole is provided on the fixed door of the oven, the tension sensor is connected to the left clamp through the hole, and the right clamp is fixedly connected to the fixed door of the oven (or in other words, the distance between the right clamp and the fixed door of the oven remains fixed).

Among them, the moving component drives the measuring unit to move, so that the pull wire is outside the oven and inside the oven, that is, the normal temperature state and the heating state, so as to measure the length of the pull wire in different states.

The function of the mobile assembly can be realized through various schemes. The preferred scheme provided by the present invention is: the mobile assembly includes a rodless cylinder, the electric platform and the fixed door of the oven are fixed on the slider of the rodless cylinder, and the connection between the rodless cylinder and the air source Connect and close to move the measuring unit. More preferably, in order to make the connection of the components more stable, the moving component also includes a fixed plate, the fixed plate is fixed on the slider of the rodless cylinder, and the electric platform and the fixed door of the oven are fixed on the fixed plate. More preferably, in order to make the movement of the measuring unit more stable, the moving assembly further includes a guide rail on which the fixed plate slides, and the guide rails are fixed under the fixed plate and on both sides of the rodless cylinder.

Among them, the electric platform drives the cable to move smoothly through the tension sensor and the fixture, so that the cable is in a tensioned and relaxed state respectively, so that the measurement is more accurate. And the length of the stay wire is calculated by the displacement sensor.

The function of the electric platform can be realized by various schemes, and the preferred scheme provided by the present invention is: the electric platform comprises a stepping motor, a platform fixed block and a platform moving block; the stepping motor is fixed on the platform fixing block, and drives the platform moving block to move ; One end of the displacement sensor is fixed on the fixed block of the platform, and the other end is fixed on the moving block of the platform; the tension sensor is fixed on the moving block of the platform. More preferably, the stepping motor drives the moving block of the platform to move through the lead screw. More preferably, in order to make the movement of the platform moving block more stable, the electric platform further includes precision guide rails, and the platform moving block slides on the precision guide rails.

The function of the displacement sensor is to display the distance moved by the electric platform, so as to calculate the length of the cable. Its embodiment can have multiple, and the preferred scheme that the present invention provides is: the displacement sensor is made up of two elements that can slide mutually, and one end of the displacement sensor is one of the components fixed on the platform fixed block, and the other end of the displacement sensor is the other end. One component is fixed on the moving block of the electric platform; the electric platform is in the initial position, that is, the state where the test cable is installed, and the initial distance of the system is L ₀ (theoretically, this position is 100mm according to the industry standard); after placing the cable, pass The movement of the electric platform makes the stay wire tense. At this time, the moving distance recorded by the displacement sensor is L ₁ , and the length of the stay wire at this time is L=L ₀ +L ₁ .

The fixed end of the clamp is called the right clamp, the other end connected to the tension sensor and movable is called the left clamp, and the pull wire is clamped between the left and right clamps. There are many ways to fix the right fixture, for example, it includes a fixing seat fixedly connected with the fixed door of the oven. In order to prevent the heat in the oven from being transferred to the tension sensor, the tension sensor and the left clamp are connected by a heat-insulated connecting rod. The pull sensor is connected with the pull wire through the clamp to accurately measure the pull force on the pull wire.

The fixed door of the oven is connected with the moving component, and moves through the moving component together with the electric platform, and the fixed door of the oven is partially sealed with the oven body through the moving component during the test.

The oven used for the test can be a traditional oven, which is composed of a box body, a resistance wire, a fan, and a temperature control part. The box part is preferably made of thermal insulation material, which has a good thermal insulation effect. The resistance wire heats the air in the oven to the specified temperature, and the function of the fan makes the temperature inside the oven uniform. The temperature control unit adopts advanced temperature control design to ensure that the temperature of the oven is within the allowable range.

In order to meet the needs of the wire drawing automatic test, the present invention also designs the oven size and oven structure suitable for the wire drawing test. Compared with the traditional oven, the volume is greatly reduced, and the accuracy of the experiment is further improved. The size of the oven is preferably 32 cm x 31 cm x 30 cm. The specially designed oven structure is the oven movable door lifting unit. The oven movable door lifting unit includes the oven movable door, steel wire rope and cylinder. The oven movable door is installed on the side of the oven body with the oven door hole and can seal the oven door hole. The oven is movable The door is connected with the cylinder rod of the cylinder fixed on the top of the oven through a steel wire rope.

After the heating of the pull wire is completed, the fixed door of the oven leaves the oven body. At this time, the movable door of the oven moves down to seal the oven door hole to prevent heat loss and facilitate the next measurement.

Preferably, the lifting unit of the movable door of the oven further includes rollers, and the wire rope is connected with the cylinder rod around the rollers to control the lifting of the movable door. Preferably, the fixed door of the oven is made of thermal insulation material, which can play a role of sealing to avoid heat loss; the cylinder is installed horizontally on the top of the oven body to further reduce the volume of the oven.

The present invention can also be provided with a bottom plate, and the bottom plate is used for fixing various parts of the measuring device, so that the whole device is integrated.

When using the above-mentioned preferred scheme to test the heat shrinkage rate of the pull wire, the movable door of the oven will seal the oven door hole, and the temperature of the oven will rise to the set value. Clamp one end of the pull wire on the right fixture and the other end on the left fixture. The electric platform moves away from the fixture so that the pull wire is under tension. When the measured value of the tension sensor reaches the specified value, the displacement sensor records the displacement of the electric platform and calculates The original length L of the guy wire.

Then the electric platform drives the left clamp to move a certain distance towards the direction close to the clamp, so that the backguy is in a relaxed state. The air cylinder is connected to the air source, and the movable door of the oven is raised through the steel wire rope, and the oven door hole is opened. At this time, the rodless cylinder is connected to the air source, and the measuring unit is moved toward the direction of the oven until the left fixture completely enters the oven through the oven door hole, and the oven is fixed. The door is pressed against the oven door hole, and the pull wire is heated in the oven.

After the heating time is reached, the rodless cylinder is connected to the air source, and the fixed door of the oven is moved away from the oven door hole, and the fixture and the pull wire are moved out of the oven. The cylinder closes the air source, the movable door of the oven descends, and the door hole of the oven is sealed, waiting for the next measurement. After the cable is cooled to room temperature in the air, the electric platform moves, so that the cable is subjected to a certain degree of tension, and the tension value is measured by the tension sensor. When it reaches the same specified value as above, the displacement sensor records the displacement of the electric platform and calculates the length of the cable. S, according to the calculation formula of heat shrinkage ε= (L－S) /L×100%, the heat shrinkage of the pull wire can be calculated.

Because the width of the pull wire itself is very narrow and the material is relatively soft, it is easy to wrinkle and twist during the heating process in the oven, and it is not easy to measure its length. The invention innovatively proposes to properly tension the pull wire by moving the electric platform to simulate the process of tensioning the pull wire when measuring the pull wire by hand, and to measure the tension force through the tension sensor to ensure that the pull wire is under different test conditions. The pulling force is the same, and the length of the cable is measured by the displacement sensor, which ensures the accuracy of the measurement length of the cable and realizes the automatic measurement of the heat shrinkage rate of the cable.

Compared with the prior art, the present invention has the advantages of:

1) The invention innovatively proposes the method of driving the cable to move through the electric platform, using the tension sensor to measure the tension on the cable, and measuring the length change of the cable through the displacement sensor, which realizes the automatic measurement of the thermal shrinkage rate of the cable.

2) The present invention designs a special oven structure. The invention designs an oven fixed door and an oven movable door, which are respectively used when the cable is installed and heated to avoid heat loss while realizing automatic measurement. The invention uses a rodless cylinder, which saves the installation space to the greatest extent. The rodless cylinder drives the movement of the measuring unit, and the action is fast, so that the reliable pressing of the fixed door of the oven to the door hole of the oven is realized. The driving cylinder of the oven movable door of the present invention adopts a horizontal installation method, which avoids the defect of large vertical size caused by the vertical installation of the traditional oven lifting door cylinder, and uses guide rails, cylinders, steel wire ropes, etc. to realize the automatic lifting of the oven movable door. high degree of automation.

3) The present invention has designed a special wire clamp. In the traditional heat shrinkage test of the pull wire, the pull wire is placed directly on the stainless steel tray. Since the pull wire itself is not completely straight, there is a certain degree of inhomogeneity when the pull wire is heated. The newly designed clamp structure ensures the uniform heating of the pull wire, the clamp operation is simple and reliable, and can clamp films of different widths for thermal shrinkage testing. The fixture designed by the invention can not only measure the heat shrinkage rate of the pull wire (width 2.5mm), but also can measure the heat shrinkage rate of the plastic film with the maximum width of 30mm and the length of 100mm, which has good versatility.

The invention has reasonable structural design and convenient use, can realize rapid measurement of the heat shrinkage rate of cigarette draw wires, has low human error and high degree of automation.

Description of drawings

Fig. 1: the schematic diagram when the backguy heating state of measuring device of the present invention;

Fig. 2: the schematic diagram when measuring device of the present invention backguy length measurement;

Figure 3: A partial view of an embodiment of the electric platform of the present invention;

Figure 4: A partial side view of a measuring device according to the invention.

Detailed ways

The concrete implementation content of the present invention is described in detail in conjunction with Fig. 1 and Fig. 2:

Example 1

As shown in Figure 1, a measuring device for the heat shrinkage rate of a cable includes a measuring unit, an oven movable door lifting unit and an oven, and the measuring unit includes a guide rail 2, a rodless cylinder 3, an electric platform 4, a tension sensor 5, and a displacement sensor 6 , fixed plate 7, connecting rod 8, oven fixed door 9, left clamp 10 and right clamp 12;

Electric platform 4 is set with reference to Fig. 3, comprises stepping motor 18, platform fixed block 22, platform moving block 20, leading screw 19 and precision guide rail 21, and stepping motor 18 is fixed on the platform fixing block 22, drives by leading screw 19 The platform moving block 20 slides on the precision guide rail 21;

The fixed plate 7 is fixed on the slider of the rodless cylinder 3, the platform fixed block 22 and the oven fixed door 9 are fixed on the fixed plate 7, the guide rail 2 is fixed on the bottom of the fixed plate 7, both sides of the rodless cylinder 3, the fixed plate 7 slides on the guide rail 2, specifically referring to Fig. 4 for setting, Fig. 4 is a side view showing the connection relationship between the guide rail 2, the rodless cylinder 3 and the fixed plate 7;

One end of the displacement sensor 6 is fixed on the platform fixed block 22, and the other end is fixed on the platform moving block 20;

The tension sensor 5 is fixed on the platform moving block 20;

The oven fixed door 9 is provided with a hole, one end of the connecting rod 8 passes through the hole and is connected with the tension sensor 5, the other end of the connecting rod 8 is connected with the left clamp 10, and the right clamp 12 is fixedly connected with the oven fixed door 9;

Oven movable door lifting unit includes oven movable door 13, roller 14, steel wire rope 15 and cylinder 16, oven movable door 13 is installed on the side of oven box body 17 that has oven door hole and can seal oven door hole, oven movable door 13 passes steel wire rope 15 is connected with the cylinder rod of the cylinder 16 that is fixed on the oven top. Wire rope 15 walks around roller 14 and is connected with cylinder rod. The oven fixed door 13 is made of thermal insulation material. 16 horizontal cylinders are installed on the top of the oven.

A bottom plate 1 is also provided for fixing the components of the above-mentioned measuring device.

Example 2

The device constructed in Example 1 was used to perform the heat shrinkage test of the drawn wire.

First, the oven movable door 13 seals the oven door hole, and the oven temperature rises to a set value. One end of the pull wire 11 is clamped on the right clamp 12, and the other end is clamped on the left clamp 10. At this time, the initial distance of the system is L ₀ (theoretically, this position is 100mm according to the industry standard). The electric platform 4 moves away from the fixture so that the pull wire 11 is subjected to tension. When the measured value of the tension sensor 5 reaches the specified value, the displacement sensor 6 records the displacement L ₁ of the electric platform 4 and calculates the original length of the pull wire 11 L=L ₀ +L ₁ .

Then the electric platform 4 drives the left clamp 10 to move a certain distance towards the direction close to the clamp, so that the stay wire 11 is in a relaxed state. The air cylinder 16 is connected to the air source, and the movable door 13 of the oven is raised through the steel wire rope 15, and the oven door hole is opened. After entering the oven, the oven fixed door 9 presses the oven door hole, and the backguy 11 is heated in the oven.

After reaching the heating time, the rodless cylinder 3 is connected to the air source, and the fixed door 9 of the oven is moved away from the oven door hole while the fixture and the backguy are moved out of the oven. Cylinder 16 closes the air supply, and oven movable door 13 descends to seal the oven door hole and wait for the next measurement. After the pull wire 11 is cooled to room temperature in the air, the initial distance of the system is L ₀ as above (theoretically, this position is 100mm according to the industry standard). The electric platform 4 moves, so that the pull wire 11 is subjected to a certain degree of tension, and the tension value is measured by the tension sensor 5. When reaching the same specified value as above, the displacement sensor 6 records the displacement L ₂ of the electric platform 4 (at this time, L ₂ may is a negative number), calculate the heated length S=L ₀ +L ₂ of the pull wire 11 . According to the calculation formula of heat shrinkage ε= (L－S)/L×100%, the heat shrinkage of the pull wire can be calculated.

Claims (8)

1. the measurement mechanism of a bracing wire percent thermal shrinkage, comprise measuring unit and baking oven, it is characterized in that measuring unit comprises moving assembly, electric platforms (4), pulling force sensor (5), displacement transducer (6), baking oven fixed gate (9), left fixture (10) and right fixture (12);

Electric platforms (4) is fixed on moving assembly with baking oven fixed gate (9), is promoted by moving assembly;

Displacement transducer (6) and pulling force sensor (5) are fixed on electric platforms (4);

Baking oven fixed gate (9) is provided with a hole, and pulling force sensor (5) is connected with left fixture (10) through hole, and right fixture (12) is fixedly connected with baking oven fixed gate (9);

Described moving assembly comprises Rodless cylinder (3), and electric platforms (4) is fixed on the slide block of Rodless cylinder (3) with baking oven fixed gate (9);

Described electric platforms (4) comprises stepper motor (18), platform fixed block (22) and platform movable block (20); It is upper that stepper motor (18) is fixed on platform fixed block (22), drives platform movement piece (20) to move; It is upper that displacement transducer (6) one end is fixed on platform fixed block (22), and the other end is fixed on platform movement piece (20); Pulling force sensor (5) is fixed on platform movement piece (20).

2. measurement mechanism as claimed in claim 1, is characterized in that moving assembly also contains fixed head (7), and fixed head (7) is fixed on the slide block of Rodless cylinder (3), and electric platforms (4) and baking oven fixed gate (9) are fixed on fixed head (7).

3. measurement mechanism as claimed in claim 1, is characterized in that moving assembly also comprises guide rail (2), and fixed head (7) is in the upper slip of guide rail (2).

4. measurement mechanism as claimed in claim 1, is characterized in that described electric platforms (4) also comprises leading screw (19), and stepper motor (18) drives platform movement piece (20) to move by leading screw (19).

5. measurement mechanism as claimed in claim 1, is characterized in that described electric platforms (4) also comprises precise guide rail (21), and platform movement piece (20) is in the upper slip of precise guide rail (21).

6. measurement mechanism as claimed in claim 1, is characterized in that pulling force sensor (5) is connected with left fixture (10) by connecting link (8).

7. measurement mechanism as claimed in claim 1, characterized by further comprising baking oven dodge gate lifting unit, baking oven dodge gate lifting unit comprises baking oven dodge gate (13), roller (14), wire rope (15) and cylinder (16), baking oven dodge gate (13) is arranged on baking oven casing (17) to be had a side of baking oven aperture of door and can seal baking oven aperture of door, and the wire rope (15) of baking oven dodge gate (13) by walking around roller (14) is connected with horizontal being arranged at the cylinder rod of the cylinder (16) at baking oven top.

8. measurement mechanism as claimed in claim 1, characterized by further comprising base plate (1), and base plate (1) is for the parts of fixation measuring device.

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