KR102465495B1 - Jig for Static Load Testing - Google Patents

Abstract

The present invention relates to a static load test jig used to measure stiffness according to the action of a static load during a stiffness test using a universal testing machine or the like. The present invention relates to a surface plate serving as a base for material testing of a test piece, a sliding guide provided on the surface plate, and a sliding guide disposed on the sliding guide and facing each other in a spaced apart or approaching direction. A length-changing member having a first support part and a second support part, one end fixed to the first support part and the other end fixed to the second support part, the length of which expands and contracts when the first support part and the second support part slide, the first support part and It includes a support rod that is seated on the second support and rotates to measure displacement due to deformation of the test piece when a static load is applied in a state in contact with the test piece.

Description

Jig for static load testing {Jig for Static Load Testing}

The present invention relates to a jig, and more particularly, to a static load test jig used to measure stiffness according to the action of a static load during a stiffness test using a universal testing machine or the like.

Material testing machines are used to test the stiffness of materials used in various industrial fields, such as various mechanical structures and construction materials, under the action of loads such as tension, compression, shear, or bending. In particular, the universal testing machine is very useful because it can perform various tests like the above in one testing machine.

1 illustrates a conventional universal testing machine, a pair of guide frames 3 having ball screws 2 are installed at regular intervals on a base block 1, and between the guide frames 3 It can be seen that the cross head block 4, which can slide in the vertical direction along the ball screw 2, is installed. In addition, a load cell 5 for applying a test load to the test piece S is mounted on the cross head block 4, and the upper portion of the cross head block 4 and the base block 1 for graphing the test piece S. A gripper 6 and a lower gripper 7 are provided.

It is common for the universal testing machine to graph the test piece using the upper gripper 6 and the lower gripper 7, but the shape or size of the test piece is difficult to graph using the upper gripper 6 or the lower gripper 7. If it is difficult to do so, a separate jig should be used. In particular, it is common to use a jig during a material test performed under the action of a static load, which is a load that does not change with time among loads received by a structure.

Since the size of the test piece that can be structurally supported is limited in the conventional jig, it cannot be used when the size of the test piece is too large or too small, making the test impossible. However, it is not only unreasonable to prepare and use various jigs according to test pieces of various sizes, but also to store and manage a large number of jigs.

Republic of Korea Patent Publication No. 10-2001-0084984 (published on September 7, 2001) Korean Patent Publication No. 10-2009-0048696 (published on May 15, 2009)

The present invention was developed to improve the above conventional problems, and an object of the present invention is to provide a static load test jig that can be operated variably to properly support a test piece in response to the size of the test piece.

The present invention for achieving the above object is a surface plate serving as a base for material testing of a test piece, a sliding guide provided on the surface plate, and a sliding guide disposed on the sliding guide and spaced apart or close to each other while facing each other. A first support part and a second support part sliding in the direction, one end fixed to the first support part and the other end fixed to the second support part, and a length-changing member whose length expands and contracts when the first support part and the second support part slide; , A static load test jig comprising a support rod seated on the first support and the second support and rotated to measure the displacement due to the deformation of the test piece when a static load is applied in a state in contact with the test piece. Provided.

In the present invention, the sliding guide part includes a guide plate made of a flat plate having a size larger than the maximum separation distance when the first support part and the second support part slide, and the first support part and the second support part on the guide plate. It may include an LM guide having an LM rail disposed long along the sliding direction of the support unit and an LM block coupled to lower ends of each of the first support unit and the second support unit.

In the present invention, the variable-length member may include: a first arm having a hollow structure having one end fixed to either one of the first support part and the second support part; And one end is fixed to the other of the first support part or the second support part, the other end is inserted into the inside of the first arm, and when the first support part or the second support part slides, a length variable member as it moves in and out against the first arm. It may be made including a second arm that allows the length of to be stretched.

In the present invention, one or more first through-holes are formed in the first arm, and a plurality of second through-holes are selectively communicated with the first through-holes according to the extent to which the length of the variable-length member is stretched in the second arm. A stopper may be further provided to stop entry and exit of the second arm by being inserted into the first through hole and the second through hole communicating therewith.

In the present invention, the first through hole and the second through hole may be formed of a nut having a female thread on an inner circumferential surface, and the stopper may be formed of a bolt having a male thread on an outer circumferential surface.

In the present invention, the support rod is formed of a round bar having a circular cross-section structure, and upper ends of the first support portion and the second support portion on which the support rod is seated may be formed in an arc shape corresponding to the circular cross section of the support rod.

The present invention configured as above has the following effects.

First, since the present invention can vary the distance between the support parts supporting the test piece according to the size of the test piece, desired test measurements can be performed while appropriately and stably supporting test pieces of various sizes.

Second, since only one jig of the present invention can support test pieces of various sizes, there is no need to use jigs of various sizes, which is advantageous in terms of cost and management.

Third, the present invention makes it possible to measure the displacement according to the deformation of the test piece without damaging the test piece through the configuration of the rotatable support rod disposed on the support, and analyze the relationship between this displacement and the static load to obtain desired data. Since it can be obtained, precise test measurement becomes possible.

1 is a diagram illustrating a conventional universal testing machine.
2 is a perspective view of an embodiment of the present invention.
3 is a perspective view illustrating a variable length member constituting the present invention.
4 is a view showing a state in which the variable length member is adjusted to the longest length in an embodiment of the present invention.
5 is a view showing a state in which the length variable member is adjusted to the shortest length in an embodiment of the present invention.
6 is a view showing a state in which a static load acts in a state in which a test piece is placed on a support rod constituting the present invention.
7 is a view showing a state in which deformation occurs in a test piece due to a static load from the appearance of FIG. 6;

Hereinafter, examples will be described in more detail so that various characteristic aspects of the present invention can be understood. In the drawings, the same or equivalent components may be denoted by the same reference numerals, and the drawings may be exaggerated or schematically illustrated for an intuitive understanding of the features of the present invention.

In this document, unless otherwise limited or inherently unacceptable, expressions for explaining the relationship between two elements, for example, expressions such as 'phase' and 'connection' are used when two elements are in direct contact with each other. It is of course allowed for a third element to be interposed between the elements of the first and second elements. Directional indications such as front and rear, left and right, or up and down are only for convenience of description and are not intended to limit the scope of the present invention.

As shown in FIG. 2, the embodiment of the present invention basically includes a surface plate 10 serving as a base for material testing of a test piece. This surface plate 10 may be a surface plate of a thick flat plate structure generally used for a material testing machine, machining equipment, assembly equipment, or the like. In particular, the surface plate 10 of the present invention can be placed on the base block of a conventional universal testing machine as shown in FIG.

A sliding guide part 20 is provided on the surface plate 10 . In this embodiment, the sliding guide part 20 is exemplified as including a separate guide plate 21 made of a flat plate structure like the surface plate 10, but the surface plate 10 itself may be applied as the guide plate 21. have. Whether the guide plate 21 is provided separately from the surface plate 10 or the surface plate 10 itself is applied as the guide plate 21, elements that slide on the guide plate 21 (ie, the first support part and the first support part to be described later) By having a size larger than the range when the two supports) slide to the maximum extent (that is, when the first support part and the second support part to be described later slide at the maximum distance from each other), the sliding elements can be prevented from being separated. be able to

A first support part 30 and a second support part 40 are disposed on the sliding guide part 20 . The first support part 30 and the second support part 40 can slide in opposite directions (ie, in a direction close to each other or in a direction spaced apart from each other) while facing each other. In this embodiment, the first support part 30 is made in the form of a pair of spaced apart pillars, and the second support part 40 is also illustrated as being made in the form of a pair of spaced apart pillars in the same way as the first support part 30. have. Unlike this, each of the first support part 30 and the second support part 40 may be made of a single wall structure, and various other modified shapes may also be considered.

A variable length member 50 connecting the first support part 30 and the second support part 40 is provided. One end of the variable length member 50 is fixed to the first support part 30, and the other end is fixed to the second support part 40. Accordingly, when the first support part 30 and the second support part 40 slide, the length of the variable length member 50 is stretched and contracted. That is, when the first support part 30 and the second support part 40 slide in a direction spaced apart from each other, the length of the variable length member 50 is extended, and the first support part 30 and the second support part 40 are When sliding in directions close to each other, the length of the variable length member 50 is reduced.

A structure of a specific embodiment of the variable length member 50 can be clearly seen in FIG. 3 . That is, the variable-length member 50 shown in FIG. 3 includes a first arm 51 having a hollow structure having one end fixed to the first support part 30 side (or the second support part 40 side); and a second arm 52 having one end fixed to the second support 40 side (or the first support 30 side) and the other end inserted into the first arm 51 . When the first support part 30 or the second support part 40 slides, the second arm 52 moves in and out partially by a predetermined length in a state where the second arm 52 is inserted into the first arm 51, and moves the length variable member 50. The entire length is stretched. As shown in FIG. 4, when the first support part 30 and the second support part 40 slide in a direction spaced apart from each other, a part of the second arm 52 is inserted into the first arm 51. While coming out, the entire length of the variable-length member 50 (ie, from one end of the first arm 51 fixed to the first support part 30 to one end of the second arm 52 fixed to the second support part 40) length to the point) is extended. 4 shows a state in which the length-changing member 50 is adjusted to the longest length in this way, but the entire length of the length-changing member 50 is such that the first support part 30 and the second support part 40 are spaced apart from each other. It is adjusted according to the sliding distance in the direction of In addition, as shown in FIG. 5 , when the first support part 30 and the second support part 40 slide in a direction approaching each other, the second arm 52 is more deeply inserted into the first arm 51. As a result, the overall length of the variable length member 50 is reduced. 5 shows a state in which the length-changing member 50 is adjusted to the shortest length.

A means for preventing the second arm 52 from moving in and out of the first arm 51 by a predetermined length may be further provided. That is, as illustrated in FIG. 3, one (or plural number is possible) first through-hole 51a is formed in the first arm 51, and the variable-length member 50 is formed in the second arm 52. A plurality of second through-holes 52a are formed at intervals so as to selectively communicate with the first through-hole 51a according to the degree of expansion and contraction of the length of the first through-hole 51a and the first through-hole 51a. A detent 53 may be provided to stop entry and exit of the second arm 52 by being inserted into the second through hole 52a communicating with the through hole 51a. Although only one pawl 53 may be provided and inserted into the first through hole 51a and any one of the second through holes 52a, when the first through hole 51a is provided in a plurality of two or more When the detents 53 are also provided in two or more and are inserted into the plurality of first through holes 51a and the second through holes 52a, respectively, the first arm 51 and the second arm 52 are not at all It is possible to maintain a more stable fixed state without being moved.

In the figure of FIG. 3, the first through hole 51a and the second through hole 52a are shown as flat holes, and the stopper 53 is shown in the form of a pin, but other forms are also possible. For example, the first through hole 51a and the second through hole 52a may be formed of a nut having a female thread formed on an inner circumferential surface, and the stopper 53 may be formed of a bolt having a male thread formed on an outer circumferential surface. According to the structure of the nut and bolt, the detent 53 is not arbitrarily separated from the state inserted into the first through hole 51a and the second through hole 52a, and the first arm ( 51) and the second arm 52 can be fixed more firmly.

Next, the above-mentioned sliding guide 20 will be additionally described. When sliding the first support part 30 and the second support part 40 on the sliding guide part 20 in order to stably support the test piece according to the size of the test piece, smooth sliding should be achieved. In addition, the sliding guide part 20 should be able to support it sufficiently and stably while enduring the load of the heavy test piece by having a large permissible load. To this end, the sliding guide 20 of this embodiment includes an LM guide on the guide plate 21 . That is, a linear motion rail, that is, an LM rail 22 is disposed on the guide plate 21 along the sliding direction of the first support part 30 and the second support part 40 . In addition, an LM block 23 that can slide on the LM rail 22 is coupled to the lower end of each of the first support part 30 and the second support part 40. As is well known, the LM rail 22 commonly used in linear motion guides is a guide mechanism on a long shaft in which guide grooves are machined, and the LM block 23 is a straight line along the LM rail 22. do exercise In particular, a number of balls or rollers are embedded in the LM block 23, so that when the LM block 23 slides along the LM rail 22, the balls move endlessly and help efficient linear motion. Having rigidity enables smooth sliding and stable support of the first support part 30 and the second support part 40 as described above.

Next, the present invention includes a pair of support rods 60 respectively seated on the first support part 30 and the second support part 40 . As shown in FIGS. 2 and 5, the support rod 60 is a first support rod seated on the upper end of the pair of first support parts 30, and a second support rod seated on the upper end of the pair of second support parts 40. Equipped with 2 support rods. The first support rod and the second support rod are opposed and disposed in parallel. These support rods 60 are rotated to measure the displacement according to the deformation of the test piece when a static load is applied in a state in contact with the test piece. In the embodiment shown in FIG. 2 , the support rod 60 is formed of a round bar having a circular cross-section. Corresponding to the structure of the support rod 60, the upper ends of the first support portion 30 and the second support portion 40 on which the support rod 60 is seated are circular arcs corresponding to the circular cross section of the support rod 60, respectively. is made in shape. The cross-sectional structure of the support rod 60 can be polygonal as well as circular, but if it has a polygonal (eg, quadrangular) cross-sectional structure, the degree of freedom of rotation is low and the upper ends of the test piece, the first support part 30, and the second support part 40 By generating a strong frictional force between the surfaces, the test piece is likely to be damaged and precise test measurement becomes difficult. On the other hand, when the cross-sectional structure of the support rod 60 is circular, as shown in FIG. 6, when the static load L acts on the test piece S, it is supported on the first support part 30 and the second support part 40. Since the rod 60 rotates freely, damage to the test piece can be prevented and precise test measurement is possible.

Although not shown in the drawings, a sensor (eg, a gyroscope sensor) for detecting a rotation angle of the support rod 60 when a static load is applied to the test piece may be disposed on the side of the support rod 60 . That is, when testing the stiffness of a test piece using a material testing machine, as shown in FIG. 7, when a static load (L) acts on the test piece (S), the test piece (S) is deformed. The contacting support rod 60 rotates. At this time, the sensor senses the rotational angle θ of the support rod 60 so that the displacement according to the deformation of the test piece can be measured, and desired data can be obtained by analyzing the relationship between the displacement and the static load. In this way, in order to be able to calculate precise test data by detecting the rotation angle θ of the support rod 60, it is preferable that the support rod 60 is formed of a round bar having a circular cross-section rather than a polygonal structure as described above.

The above-described variable length member 50 of the present invention may be implemented by various means other than those illustrated in FIG. 3 . For example, it is a ball/hydraulic cylinder device or a bellows type pipe.

Having described embodiments of the present invention, these embodiments will be helpful in understanding various aspects and features of the present invention. Elements presented in these embodiments may be selectively combined with each other, and another embodiment not previously described in this document may be presented by such a combination.

Hereinafter, claims for defining the scope of the present invention are described. The element(s) recited in the claims may be variously changed, modified, and replaced with equivalents without departing from the technical spirit of the invention. The reference numerals in the claims, if any, are intended to aid easy and intuitive understanding of the claimed inventions or their elements, and do not limit the scope of the claimed inventions.

10: surface plate 20: sliding guide part
21: guide plate 22: LM rail
23: LM block 30: first support
40: second support 50: length variable member
51: first arm 51a: first through hole
52: second arm 52a: second through hole
53: detent 60: support rod
S: test piece

Claims (6)

A surface plate that serves as a base for material testing of test pieces;
a sliding guide provided on the surface plate;
Each of the first and second supports, the first support and the second support, disposed opposite to each other on the sliding guide so as to slide in a direction away from or approaching each other along the sliding guide consists of a pair of spaced apart pillars ;
a variable length member having one end fixed to the first support and the other end fixed to the second support, and configured to be stretchable according to the distance between the first and second supports; and
It is seated on the upper ends of the first and second supports and includes a support rod on which a test piece is placed,
The support rod includes a first support rod seated on the first support portion and a second support rod seated on the second support portion, the first support rod and the second support rod are disposed parallel to each other,
The support rod is made of a round bar with a circular cross-section structure, and the upper ends of the first support portion and the second support portion on which the support rod is seated are made in an arc shape corresponding to the circular cross section of the support rod, respectively, on the first support portion and the second support portion. A static load test jig, characterized in that the support rod can be rotated. The method of claim 1, wherein the variable length member,
a first arm having a hollow structure having one end fixed to the first support part; and
One end is fixed to the second support, the other end is inserted into the first arm and is movable along the first arm, and the first or second support slides in a direction away from or close to each other along the sliding guide. The jig for a static load test, characterized in that it comprises a second arm that allows the length of the variable-length member to expand and contract as it is. According to claim 2,
At least one first through hole is formed in the first arm,
In the second arm, a plurality of second through-holes are formed at intervals so as to selectively communicate with the first through-holes according to the extent to which the length of the variable-length member is stretched.
A static load test jig, characterized in that further provided with a detent for stopping the entry and exit of the second arm by being inserted into the first through-hole and the second through-hole communicating therewith. delete delete delete

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