JPH044935B2 - - Google Patents

Description

[Detailed description of the invention]

a.Field of Industrial Application The present invention relates to a biaxial stretching tester for measuring the properties of sheet-like materials such as various films, paper, cloth, canvas, textiles, etc. by stretching them biaxially simultaneously or sequentially. This relates to a clip tenter-type biaxial stretching test in which each side of the sample to be measured is held with a number of clips and the sample is stretched by increasing the distance between the clips, and is particularly suitable for measuring characteristics at low magnification. It is something that b. Prior Art In general, the biaxial stretching test equipment required to examine the biaxial tensile properties of sheet-like materials as described above has the following performance characteristics:
(1) Deformation occurs uniformly within the sample, (2) Deformation amount can be observed accurately, (3) Stress in each axial direction can be accurately measured, (4) Deformation amount in two directions or It is desired that the film satisfies the requirements of being able to stretch while maintaining a constant relationship between stresses and being able to easily analyze the results. Conventional biaxial stretching testing machines can be roughly divided into
7194, etc., in which each convex end of a cross-shaped sample is grasped and the sample is stretched in biaxial directions, and Japanese Patent Publication No. 45-40033 and Japanese Patent Publication No. 45-40600 There are two types of methods, such as those shown in Japanese Patent Publication No. 1, etc., in which each side of a rectangular sample is held with several groups of clips and the sample is stretched. In recent years, the latter type of clip tenter type has been widely used. By the way, in the above-mentioned conventional clip tenter type, as a mechanism for expanding the interval between clips, the arm of the clip is engaged with a fixed bar and a movable bar using a roller bearing, as shown in Japanese Patent Publication No. 45-40033. or Jikko 49-
There are devices that use a pantograph mechanism as disclosed in Japanese Patent No. 26692, but in all of these, only two adjacent sides of a rectangular sample move to stretch the sample, and the other two sides facing these are fixed. Therefore, various conditions such as the amount of deformation, deformation rate, stress, etc. are different between the deformation of the sample near the tensile part and the deformation of the sample near the fixed part, so it is difficult to compare test results for different samples. I had a problem where I couldn't do it. In particular, when measuring at a low stretching ratio, the error caused by the above-mentioned points becomes relatively large, making it difficult to obtain reliable data. c. Purpose of the present invention The present invention was made in view of the current situation, and
The object of the present invention is to provide a biaxial stretching tester that satisfies the above-mentioned performance and can perform stable measurements with good reproducibility even at low stretching ratios of 2 times or less. d Structure and operation of the present invention The present invention that achieves the above object has the following structure. That is, the present invention is a clip tenter type biaxial stretching tester in which each side of a sheet-like sample is gripped with a large number of clips, and the sample is stretched in two axial directions by increasing the interval between the clips. The means for increasing the distance between the clips includes a plurality of links constituting the pantograph mechanism, a pin connecting the two links, and a plurality of holders each having a clip at one end, each of which is provided with a sliding groove. The links are slidably engaged by pins in this sliding groove, and every other holding base is pivotally connected by the links and pins at fixed points in the area other than the sliding groove, and the nodes are is formed. When trying to increase the clip interval, the link rotates around the pin connection point, and the engagement point slides along the sliding groove, causing the pantograph mechanism to operate (the intersecting angle of the link changes to the opening angle). ). The present invention has been made as a result of various investigations into countermeasures for the above-mentioned problem, and it has been discovered that the main cause of the problem lies in the non-uniformity of the movement of the clip during stretching. For example, in a conventional device using a pantograph mechanism, the distance between the clips near the moving point is large, and the distance between the clips near the fixed point is small.
The spacing between the clips is not uniformly increased during stretching, and its time course is also not constant. Furthermore, it is presumed that the effect is particularly large at low draw ratios because the clip spacing is small. Therefore, to solve the problem, it is necessary to equalize the movement of the clip during stretching. The testing machine of the present invention is connected to a support stand every other time,
A sliding groove is also provided at the intersection of the links and engages with the support base, so the movement of the support base near the moving point by the link is quickly transmitted by the pantograph mechanism to both the center and the ends, and the clip interval is It is averaged and the problem of non-uniform stretching is solved. The pantograph mechanism, which forms the main part of the present invention, has links of appropriate length to equalize movement, and can be engaged with a holding base having a groove with an appropriate sliding length at the intersection of the links. That's fine. The selection is made taking into consideration the overall stroke of the pantograph, the number of clips, the initial clip interval, etc., but if the links can be connected to the support at every other node, the effect of uniform stretching can be obtained. Furthermore, in the present invention, when a rectangular sample is stretched in the orthogonal direction, the clips corresponding to the midpoints of each side of the sample are fixed and the clips are expanded to both sides. Compared to this, the stroke is halved, which has the effect of allowing measurements to be made with higher accuracy and better reproducibility. As described above, the present invention is extremely superior in that it not only solves the problems of conventional devices, but also enables accurate measurement of biaxial stretching properties. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be explained below with reference to the drawings based on examples suitable for measuring the biaxial stretching properties of polymer films. FIG. 1 is a configuration diagram of the biaxial stretching section of the above embodiment,
FIG. 2 is a detailed view of the enlargement mechanism, and FIG. 3 is a partial side sectional view thereof. In FIG. 1, the horizontal axis is abbreviated as X and the vertical axis as Y. In the figure, 1 is a drive motor, 2 and 3 are drive shafts in the X direction, and 4 and 5 are drive shafts in the Y direction. ing. The drive shaft 2 is directly connected to the motor 1, and the drive shaft 3 is driven by an intermediate shaft 6 connected to the drive shaft 2 by gears 2a, 6a via gears 6b, 3a. On the other hand, the drive shafts 4, 5 are gears 2b, 7a', 7a.
The gear 7 is connected to the motor 1 by the intermediate shaft 7.
b, 4a and gears 7c, 5a. That is, the drive shafts 2, 3, 4, 5 are the motor 1
It is designed to be driven at the same time. Note that reference numeral 8 in the figure indicates an attachment portion to the pedestal (not shown). 11 and 12 in the figure are moving tables that move in the X direction.
Reference numerals 13 and 14 are movable tables that move parallel to each other in the Y direction below. The moving tables 11 and 12 are located on both sides of the midpoint of the drive shafts 2 and 3, and the gear 1 is
1a, 11b and gears 12a, 12b. Further, the movable tables 13 and 14 are similarly screwed to the drive shafts 4 and 5. In this way, the movable tables 11, 12, 13 and 14 are connected to the drive shaft 2,
3, 4, and 5 move simultaneously so that the area they enclose is expanded. Furthermore, on the upper surfaces of the movable tables 11, 12, 13 and 14, there are engagement grooves 11c, which guide clips to be described later in the axial direction.
12c, 13c and 14c are provided. 21, 22, 23, and 24 in the figure are end point blocks to which both ends of a pantograph mechanism to be described later are fixed, and are movably provided at positions corresponding to the intersections of the movable bases 11, 12 and the movable bases 13, 14. There is.
For example, the end point block 21 is located on the intersection of the movable base 11 and the movable base 13, and the engagement groove 11
c, 13c, and is movably provided on the movable table 11. Other endpoint blocks 22, 23,
24 is also similar to this. End point block 21, 2
2, 23, and 24 are adapted to move as the movable tables 11, 12, 13, and 14 move so that they are located on the intersection of the movable tables 11, 12 and the movable tables 13, 14. And end point blocks 21, 22, 23, 24
There are engaging grooves 11c, 12c, 13c, 14c between the
The holding base 30 of each clip C and its group of clips is movably moved in the X direction and the Y direction while being guided by each
is installed. In addition, the moving tables 11, 12, 1
The clip _C0 located at the midpoint of each of movable bases 11, 12, 13 and
It is fixed to each of 4. The holding platform 30 is connected to the magnifying means. Second
The details will be explained using the end point block 21 as an example with reference to the drawings. Enlargement means are links 31a, 31
b are connected with pins 32, 33, and 34, and the holding base 30
and the nodes of the link are pins 32, 33, 34.
are connected at fixed points on the holder via pins 34, and the intersections of the links engage in the sliding grooves of the holder via pins 34 to form a pantograph mechanism. The pantograph and the holding base are rotatably connected via the pin 32 at a fixed point at one end of the holding base at a node (specifically, connected by the pin 32) that is the fixed position, and at the other end. In the specific example of the node, the point engaged by the pin 34 is moved in the axial direction of the holder via the engagement roller 34' provided coaxially with the pin 34 by the sliding groove 38 provided in the axial direction of the holder. It is slidably engaged with and rotatably coupled around the pin 34. One end of the pantograph is connected to the upper end of the end point block 21 in exactly the same way as it is connected to the holder. The other end is similarly connected to the holder of the origin clip C ₀ shown in FIG. A four-sided enlarging mechanism for gripping the sample S shown in FIG. 1 is configured in exactly the same manner. By the way, as shown in FIG.
1, and can be stably moved on the moving table 11. Further, the clip C is a known type suitable for a polymer film which holds the sample S with a head H supported by a spring (not shown). A strain gauge (not shown) is attached to the origin clip C ₀ at the midpoint of each side to measure the stretching stress. Moreover, the above-mentioned biaxial stretching mechanism is installed in a constant temperature bath whose temperature can be controlled, so that it can be tested at any set stretching temperature. In this way, the temperature, stretching stress,
Stretching speed, magnification, etc. can be set, and stretching data for each sample controlled by the settings can be obtained. Next, a biaxial stretching test of sample S with the above configuration will be explained. A rectangular or square sample S to be tested is set in the clip C at the reset position shown in FIG. Next, when the motor 1 is started, the drive shafts 2, 3, 4, and 5 rotate due to the above-described configuration, and the movable tables 11, 12, 13, and 14 move at the same speed in the direction of the arrow in the figure. As the movable tables 11, 12, 13 and 14 move, the end point blocks 21, 2
2, 23 and 24 move in the enlargement direction. As mentioned above, the origin clip _C0 located at the midpoint of each side of each sample is fixed to each moving stage 11, 12, 13 or 14, so the end point block 21,
By moving 22, 23 or 24, each side of the sample S is stretched to both sides of the origin clip _C0 .
At this time, each clip C is moved by a pantograph mechanism as shown in FIG. 2, so the intervals between each clip C are uniformly expanded both temporally and spatially. Therefore, it has become possible to perform a stretching test that is uniform both temporally and spatially, and with good reproducibility. In addition, since the center of the sample S is the origin, there is less local stress concentration compared to conventional devices with two fixed sides, making accurate measurements possible, and the required travel distance for the same magnification test. is half that of conventional equipment, which is an advantage in terms of measurement accuracy. When the end point such as a predetermined magnification or breakage is reached, the motor 1 is turned off and the test ends. Note that the above operations are performed on the movable tables 11, 12, 13.
It is also possible to automate the process by providing a detector for detecting the amount of movement, position, etc. of 14 and 14, which is convenient. Next, Table 1 shows the measurement results of the differences in clip spacing according to the examples. Table 1 shows the difference between the maximum and minimum clip distances when a sample of polyethylene terephthalate film measuring 100 mm x 100 mm was stretched at a temperature of 80° C. to each magnification shown in the table.
The comparative example is a heavy duty type stretching tester manufactured by TMLong in the United States.
Stretcher).

[Table] From Table 1, it can be seen that in this example, there is no difference in the clip spacing regardless of the magnification, and ideal stretching with equal spacing is achieved. Although the present invention has been described above based on examples, the present invention is not limited to these examples. Although the case of simultaneous biaxial stretching has been explained, it goes without saying that stretching may be performed by changing the stretching ratio and deformation speed independently for each axis. This can be easily achieved by driving the Although a configuration has been shown in which the clips are fixed at the midpoints of the four sides of a rectangular sample and stretched to both sides, the magnifying mechanism consisting of the pantograph of the present invention can also be applied to conventional devices, and improves measurement reproducibility, accurate measurement, etc. It is clear from the spirit of the present invention that the same effect can be obtained with the following. The present invention is a pantograph mechanism in which the clip enlarging means is connected to each holding stand, and every other one is connected to the holding stand, and furthermore, a sliding groove is provided at the intersection of the pantographs to engage with the holding stand and a pin. It has a structure that equalizes the movement of the clip as it is stretched. Therefore, it contributes to improving the accuracy, reproducibility, etc. of measuring the biaxial stretching properties of sheet-like materials.

[Brief explanation of drawings]

FIG. 1 is a block diagram of the biaxial stretching section of the embodiment of the present invention, FIG. 2 is a detailed view (partial plan view) of the clip enlarging means of the embodiment of FIG. 1, and FIG. FIG. 3 is a side view of the means. In the drawings 1... Motor, 2, 3, 4, 5... Drive shaft, 1
1, 12, 13, 14...Moving table, 21, 22,
23, 24...End point block, C...Clip,
30... Holding stand, 31a, 31b... Pantograph link, 32, 33, 34... Pin, 38...
...It is a sliding groove.

Claims (1)

[Scope of Claims] 1. A clip tenter-type biaxial stretching machine capable of holding the peripheral edge of a sheet-like sample with a plurality of clips and then stretching and deforming the sample in two different directions using an expanding means that expands the distance between the clips. In,
The enlarging means consists of a plurality of holders that hold individual clips, a plurality of links that constitute a pantograph mechanism, and a pin that connects the holder and the links, and the links are connected to slides provided on the individual holders. The links are engaged by pins in the moving grooves, and the links are pivotally connected by pins at fixed points other than the sliding grooves to every other holding base to form nodes, and the links are engaged when the clip interval is expanded. A biaxial stretching tester characterized in that a pantograph mechanism functions when two joined links open at an intersection point with a pin and the pin slides along a sliding groove. 2 Rectangular or square samples at right angles to each other 2
This is a clip tenter-type biaxial stretching machine capable of stretching and deforming the sample in the following directions: the holding stand for the clips that grips the midpoint of each side of the sample is fixed, and the other holding stands are moved to expand the distance between the clips. A biaxial stretching tester according to claim 1.